Remove `Send + Sync` bounds when `no-std`

diff --git a/lightning-background-processor/src/lib.rs b/lightning-background-processor/src/lib.rs
index 4d13925..47a731f 100644
--- a/lightning-background-processor/src/lib.rs
+++ b/lightning-background-processor/src/lib.rs
@@ -300,7 +300,7 @@ where
 
 /// Updates scorer based on event and returns whether an update occurred so we can decide whether
 /// to persist.
-fn update_scorer<'a, S: Deref<Target = SC> + Send + Sync, SC: 'a + WriteableScore<'a>>(
+fn update_scorer<'a, S: Deref<Target = SC>, SC: 'a + WriteableScore<'a>>(
 	scorer: &'a S, event: &Event, duration_since_epoch: Duration,
 ) -> bool {
 	match event {
@@ -887,10 +887,8 @@ pub async fn process_events_async<
 	P: Deref,
 	EventHandlerFuture: core::future::Future<Output = Result<(), ReplayEvent>>,
 	EventHandler: Fn(Event) -> EventHandlerFuture,
-	ES: Deref + Send,
-	M: Deref<Target = ChainMonitor<<CM::Target as AChannelManager>::Signer, CF, T, F, L, P, ES>>
-		+ Send
-		+ Sync,
+	ES: Deref,
+	M: Deref<Target = ChainMonitor<<CM::Target as AChannelManager>::Signer, CF, T, F, L, P, ES>>,
 	CM: Deref,
 	OM: Deref,
 	PGS: Deref<Target = P2PGossipSync<G, UL, L>>,
@@ -901,7 +899,7 @@ pub async fn process_events_async<
 	O: Deref,
 	K: Deref,
 	OS: Deref<Target = OutputSweeper<T, D, F, CF, K, L, O>>,
-	S: Deref<Target = SC> + Send + Sync,
+	S: Deref<Target = SC>,
 	SC: for<'b> WriteableScore<'b>,
 	SleepFuture: core::future::Future<Output = bool> + core::marker::Unpin,
 	Sleeper: Fn(Duration) -> SleepFuture,
@@ -1356,15 +1354,13 @@ pub async fn process_events_async_with_kv_store_sync<
 	T: Deref,
 	F: Deref,
 	G: Deref<Target = NetworkGraph<L>>,
-	L: Deref + Send + Sync,
+	L: Deref,
 	P: Deref,
 	EventHandlerFuture: core::future::Future<Output = Result<(), ReplayEvent>>,
 	EventHandler: Fn(Event) -> EventHandlerFuture,
-	ES: Deref + Send,
-	M: Deref<Target = ChainMonitor<<CM::Target as AChannelManager>::Signer, CF, T, F, L, P, ES>>
-		+ Send
-		+ Sync,
-	CM: Deref + Send + Sync,
+	ES: Deref,
+	M: Deref<Target = ChainMonitor<<CM::Target as AChannelManager>::Signer, CF, T, F, L, P, ES>>,
+	CM: Deref,
 	OM: Deref,
 	PGS: Deref<Target = P2PGossipSync<G, UL, L>>,
 	RGS: Deref<Target = RapidGossipSync<G, L>>,
@@ -1374,7 +1370,7 @@ pub async fn process_events_async_with_kv_store_sync<
 	O: Deref,
 	K: Deref,
 	OS: Deref<Target = OutputSweeperSync<T, D, F, CF, K, L, O>>,
-	S: Deref<Target = SC> + Send + Sync,
+	S: Deref<Target = SC>,
 	SC: for<'b> WriteableScore<'b>,
 	SleepFuture: core::future::Future<Output = bool> + core::marker::Unpin,
 	Sleeper: Fn(Duration) -> SleepFuture,
diff --git a/lightning/src/events/bump_transaction/mod.rs b/lightning/src/events/bump_transaction/mod.rs
index 3e8c647..ec55c92 100644
--- a/lightning/src/events/bump_transaction/mod.rs
+++ b/lightning/src/events/bump_transaction/mod.rs
@@ -391,13 +391,13 @@ pub trait CoinSelectionSource {
 	fn select_confirmed_utxos<'a>(
 		&'a self, claim_id: ClaimId, must_spend: Vec<Input>, must_pay_to: &'a [TxOut],
 		target_feerate_sat_per_1000_weight: u32, max_tx_weight: u64,
-	) -> AsyncResult<'a, CoinSelection>;
+	) -> AsyncResult<'a, CoinSelection, ()>;
 	/// Signs and provides the full witness for all inputs within the transaction known to the
 	/// trait (i.e., any provided via [`CoinSelectionSource::select_confirmed_utxos`]).
 	///
 	/// If your wallet does not support signing PSBTs you can call `psbt.extract_tx()` to get the
 	/// unsigned transaction and then sign it with your wallet.
-	fn sign_psbt<'a>(&'a self, psbt: Psbt) -> AsyncResult<'a, Transaction>;
+	fn sign_psbt<'a>(&'a self, psbt: Psbt) -> AsyncResult<'a, Transaction, ()>;
 }
 
 /// An alternative to [`CoinSelectionSource`] that can be implemented and used along [`Wallet`] to
@@ -406,17 +406,17 @@ pub trait CoinSelectionSource {
 /// For a synchronous version of this trait, see [`sync::WalletSourceSync`].
 pub trait WalletSource {
 	/// Returns all UTXOs, with at least 1 confirmation each, that are available to spend.
-	fn list_confirmed_utxos<'a>(&'a self) -> AsyncResult<'a, Vec<Utxo>>;
+	fn list_confirmed_utxos<'a>(&'a self) -> AsyncResult<'a, Vec<Utxo>, ()>;
 	/// Returns a script to use for change above dust resulting from a successful coin selection
 	/// attempt.
-	fn get_change_script<'a>(&'a self) -> AsyncResult<'a, ScriptBuf>;
+	fn get_change_script<'a>(&'a self) -> AsyncResult<'a, ScriptBuf, ()>;
 	/// Signs and provides the full [`TxIn::script_sig`] and [`TxIn::witness`] for all inputs within
 	/// the transaction known to the wallet (i.e., any provided via
 	/// [`WalletSource::list_confirmed_utxos`]).
 	///
 	/// If your wallet does not support signing PSBTs you can call `psbt.extract_tx()` to get the
 	/// unsigned transaction and then sign it with your wallet.
-	fn sign_psbt<'a>(&'a self, psbt: Psbt) -> AsyncResult<'a, Transaction>;
+	fn sign_psbt<'a>(&'a self, psbt: Psbt) -> AsyncResult<'a, Transaction, ()>;
 }
 
 /// A wrapper over [`WalletSource`] that implements [`CoinSelection`] by preferring UTXOs that would
@@ -608,7 +608,7 @@ where
 	fn select_confirmed_utxos<'a>(
 		&'a self, claim_id: ClaimId, must_spend: Vec<Input>, must_pay_to: &'a [TxOut],
 		target_feerate_sat_per_1000_weight: u32, max_tx_weight: u64,
-	) -> AsyncResult<'a, CoinSelection> {
+	) -> AsyncResult<'a, CoinSelection, ()> {
 		Box::pin(async move {
 			let utxos = self.source.list_confirmed_utxos().await?;
 			// TODO: Use fee estimation utils when we upgrade to bitcoin v0.30.0.
@@ -659,7 +659,7 @@ where
 		})
 	}
 
-	fn sign_psbt<'a>(&'a self, psbt: Psbt) -> AsyncResult<'a, Transaction> {
+	fn sign_psbt<'a>(&'a self, psbt: Psbt) -> AsyncResult<'a, Transaction, ()> {
 		self.source.sign_psbt(psbt)
 	}
 }
diff --git a/lightning/src/events/bump_transaction/sync.rs b/lightning/src/events/bump_transaction/sync.rs
index 50e8a8a..c987b87 100644
--- a/lightning/src/events/bump_transaction/sync.rs
+++ b/lightning/src/events/bump_transaction/sync.rs
@@ -58,17 +58,17 @@ impl<T: Deref> WalletSource for WalletSourceSyncWrapper<T>
 where
 	T::Target: WalletSourceSync,
 {
-	fn list_confirmed_utxos<'a>(&'a self) -> AsyncResult<'a, Vec<Utxo>> {
+	fn list_confirmed_utxos<'a>(&'a self) -> AsyncResult<'a, Vec<Utxo>, ()> {
 		let utxos = self.0.list_confirmed_utxos();
 		Box::pin(async move { utxos })
 	}
 
-	fn get_change_script<'a>(&'a self) -> AsyncResult<'a, ScriptBuf> {
+	fn get_change_script<'a>(&'a self) -> AsyncResult<'a, ScriptBuf, ()> {
 		let script = self.0.get_change_script();
 		Box::pin(async move { script })
 	}
 
-	fn sign_psbt<'a>(&'a self, psbt: Psbt) -> AsyncResult<'a, Transaction> {
+	fn sign_psbt<'a>(&'a self, psbt: Psbt) -> AsyncResult<'a, Transaction, ()> {
 		let signed_psbt = self.0.sign_psbt(psbt);
 		Box::pin(async move { signed_psbt })
 	}
@@ -171,7 +171,7 @@ where
 	fn select_confirmed_utxos<'a>(
 		&'a self, claim_id: ClaimId, must_spend: Vec<Input>, must_pay_to: &'a [TxOut],
 		target_feerate_sat_per_1000_weight: u32, max_tx_weight: u64,
-	) -> AsyncResult<'a, CoinSelection> {
+	) -> AsyncResult<'a, CoinSelection, ()> {
 		let coins = self.0.select_confirmed_utxos(
 			claim_id,
 			must_spend,
@@ -182,7 +182,7 @@ where
 		Box::pin(async move { coins })
 	}
 
-	fn sign_psbt<'a>(&'a self, psbt: Psbt) -> AsyncResult<'a, Transaction> {
+	fn sign_psbt<'a>(&'a self, psbt: Psbt) -> AsyncResult<'a, Transaction, ()> {
 		let psbt = self.0.sign_psbt(psbt);
 		Box::pin(async move { psbt })
 	}
diff --git a/lightning/src/sign/mod.rs b/lightning/src/sign/mod.rs
index 471b006..88a9f32 100644
--- a/lightning/src/sign/mod.rs
+++ b/lightning/src/sign/mod.rs
@@ -1064,7 +1064,7 @@ pub trait ChangeDestinationSource {
 	///
 	/// This method should return a different value each time it is called, to avoid linking
 	/// on-chain funds controlled to the same user.
-	fn get_change_destination_script<'a>(&'a self) -> AsyncResult<'a, ScriptBuf>;
+	fn get_change_destination_script<'a>(&'a self) -> AsyncResult<'a, ScriptBuf, ()>;
 }
 
 /// A synchronous helper trait that describes an on-chain wallet capable of returning a (change) destination script.
@@ -1096,7 +1096,7 @@ impl<T: Deref> ChangeDestinationSource for ChangeDestinationSourceSyncWrapper<T>
 where
 	T::Target: ChangeDestinationSourceSync,
 {
-	fn get_change_destination_script<'a>(&'a self) -> AsyncResult<'a, ScriptBuf> {
+	fn get_change_destination_script<'a>(&'a self) -> AsyncResult<'a, ScriptBuf, ()> {
 		let script = self.0.get_change_destination_script();
 		Box::pin(async move { script })
 	}
diff --git a/lightning/src/util/async_poll.rs b/lightning/src/util/async_poll.rs
index 3edfd52..7161bc7 100644
--- a/lightning/src/util/async_poll.rs
+++ b/lightning/src/util/async_poll.rs
@@ -93,11 +93,11 @@ pub(crate) fn dummy_waker() -> Waker {
 }
 
 #[cfg(feature = "std")]
-/// A type alias for a future that returns a result of type T.
-pub type AsyncResult<'a, T> = Pin<Box<dyn Future<Output = Result<T, ()>> + 'a + Send>>;
+/// A type alias for a future that returns a result of type `T` or error `E`.
+pub type AsyncResult<'a, T, E> = Pin<Box<dyn Future<Output = Result<T, E>> + 'a + Send>>;
 #[cfg(not(feature = "std"))]
-/// A type alias for a future that returns a result of type T.
-pub type AsyncResult<'a, T> = Pin<Box<dyn Future<Output = Result<T, ()>> + 'a>>;
+/// A type alias for a future that returns a result of type `T` or error `E`.
+pub type AsyncResult<'a, T, E> = Pin<Box<dyn Future<Output = Result<T, E>> + 'a>>;
 
 /// Marker trait to optionally implement `Sync` under std.
 #[cfg(feature = "std")]
diff --git a/lightning/src/util/persist.rs b/lightning/src/util/persist.rs
index 0b4ba19..434e16d 100644
--- a/lightning/src/util/persist.rs
+++ b/lightning/src/util/persist.rs
@@ -34,7 +34,7 @@ use crate::chain::transaction::OutPoint;
 use crate::ln::types::ChannelId;
 use crate::sign::{ecdsa::EcdsaChannelSigner, EntropySource, SignerProvider};
 use crate::sync::Mutex;
-use crate::util::async_poll::{dummy_waker, MaybeSend, MaybeSync};
+use crate::util::async_poll::{dummy_waker, AsyncResult, MaybeSend, MaybeSync};
 use crate::util::logger::Logger;
 use crate::util::native_async::FutureSpawner;
 use crate::util::ser::{Readable, ReadableArgs, Writeable};
@@ -160,7 +160,7 @@ where
 {
 	fn read(
 		&self, primary_namespace: &str, secondary_namespace: &str, key: &str,
-	) -> Pin<Box<dyn Future<Output = Result<Vec<u8>, io::Error>> + 'static + Send>> {
+	) -> AsyncResult<'static, Vec<u8>, io::Error> {
 		let res = self.0.read(primary_namespace, secondary_namespace, key);
 
 		Box::pin(async move { res })
@@ -168,7 +168,7 @@ where
 
 	fn write(
 		&self, primary_namespace: &str, secondary_namespace: &str, key: &str, buf: Vec<u8>,
-	) -> Pin<Box<dyn Future<Output = Result<(), io::Error>> + 'static + Send>> {
+	) -> AsyncResult<'static, (), io::Error> {
 		let res = self.0.write(primary_namespace, secondary_namespace, key, buf);
 
 		Box::pin(async move { res })
@@ -176,7 +176,7 @@ where
 
 	fn remove(
 		&self, primary_namespace: &str, secondary_namespace: &str, key: &str,
-	) -> Pin<Box<dyn Future<Output = Result<(), io::Error>> + 'static + Send>> {
+	) -> AsyncResult<'static, (), io::Error> {
 		let res = self.0.remove(primary_namespace, secondary_namespace, key);
 
 		Box::pin(async move { res })
@@ -184,7 +184,7 @@ where
 
 	fn list(
 		&self, primary_namespace: &str, secondary_namespace: &str,
-	) -> Pin<Box<dyn Future<Output = Result<Vec<String>, io::Error>> + 'static + Send>> {
+	) -> AsyncResult<'static, Vec<String>, io::Error> {
 		let res = self.0.list(primary_namespace, secondary_namespace);
 
 		Box::pin(async move { res })
@@ -222,7 +222,7 @@ pub trait KVStore {
 	/// [`ErrorKind::NotFound`]: io::ErrorKind::NotFound
 	fn read(
 		&self, primary_namespace: &str, secondary_namespace: &str, key: &str,
-	) -> Pin<Box<dyn Future<Output = Result<Vec<u8>, io::Error>> + 'static + Send>>;
+	) -> AsyncResult<'static, Vec<u8>, io::Error>;
 	/// Persists the given data under the given `key`.
 	///
 	/// The order of multiple writes to the same key needs to be retained while persisting
@@ -242,7 +242,7 @@ pub trait KVStore {
 	/// Will create the given `primary_namespace` and `secondary_namespace` if not already present in the store.
 	fn write(
 		&self, primary_namespace: &str, secondary_namespace: &str, key: &str, buf: Vec<u8>,
-	) -> Pin<Box<dyn Future<Output = Result<(), io::Error>> + 'static + Send>>;
+	) -> AsyncResult<'static, (), io::Error>;
 	/// Removes any data that had previously been persisted under the given `key`.
 	///
 	/// Returns successfully if no data will be stored for the given `primary_namespace`,
@@ -250,7 +250,7 @@ pub trait KVStore {
 	/// invokation or not.
 	fn remove(
 		&self, primary_namespace: &str, secondary_namespace: &str, key: &str,
-	) -> Pin<Box<dyn Future<Output = Result<(), io::Error>> + 'static + Send>>;
+	) -> AsyncResult<'static, (), io::Error>;
 	/// Returns a list of keys that are stored under the given `secondary_namespace` in
 	/// `primary_namespace`.
 	///
@@ -258,7 +258,7 @@ pub trait KVStore {
 	/// returned keys. Returns an empty list if `primary_namespace` or `secondary_namespace` is unknown.
 	fn list(
 		&self, primary_namespace: &str, secondary_namespace: &str,
-	) -> Pin<Box<dyn Future<Output = Result<Vec<String>, io::Error>> + 'static + Send>>;
+	) -> AsyncResult<'static, Vec<String>, io::Error>;
 }
 
 /// Provides additional interface methods that are required for [`KVStore`]-to-[`KVStore`]
diff --git a/lightning/src/util/sweep.rs b/lightning/src/util/sweep.rs
index 99a6296..95a7585 100644
--- a/lightning/src/util/sweep.rs
+++ b/lightning/src/util/sweep.rs
@@ -35,11 +35,10 @@ use bitcoin::{BlockHash, ScriptBuf, Transaction, Txid};
 
 use core::future::Future;
 use core::ops::Deref;
-use core::pin::Pin;
 use core::sync::atomic::{AtomicBool, Ordering};
 use core::task;
 
-use super::async_poll::dummy_waker;
+use super::async_poll::{dummy_waker, AsyncResult};
 
 /// The number of blocks we wait before we prune the tracked spendable outputs.
 pub const PRUNE_DELAY_BLOCKS: u32 = ARCHIVAL_DELAY_BLOCKS + ANTI_REORG_DELAY;
@@ -604,9 +603,7 @@ where
 		sweeper_state.dirty = true;
 	}
 
-	fn persist_state<'a>(
-		&self, sweeper_state: &SweeperState,
-	) -> Pin<Box<dyn Future<Output = Result<(), io::Error>> + 'a + Send>> {
+	fn persist_state<'a>(&self, sweeper_state: &SweeperState) -> AsyncResult<'a, (), io::Error> {
 		let encoded = sweeper_state.encode();
 
 		self.kv_store.write(
diff --git a/lightning/src/util/test_utils.rs b/lightning/src/util/test_utils.rs
index 4c5b0e7..1931287 100644
--- a/lightning/src/util/test_utils.rs
+++ b/lightning/src/util/test_utils.rs
@@ -50,6 +50,7 @@ use crate::sign::{self, ReceiveAuthKey};
 use crate::sign::{ChannelSigner, PeerStorageKey};
 use crate::sync::RwLock;
 use crate::types::features::{ChannelFeatures, InitFeatures, NodeFeatures};
+use crate::util::async_poll::AsyncResult;
 use crate::util::config::UserConfig;
 use crate::util::dyn_signer::{
 	DynKeysInterface, DynKeysInterfaceTrait, DynPhantomKeysInterface, DynSigner,
@@ -1011,13 +1012,13 @@ impl TestStore {
 impl KVStore for TestStore {
 	fn read(
 		&self, primary_namespace: &str, secondary_namespace: &str, key: &str,
-	) -> Pin<Box<dyn Future<Output = Result<Vec<u8>, io::Error>> + 'static + Send>> {
+	) -> AsyncResult<'static, Vec<u8>, io::Error> {
 		let res = self.read_internal(&primary_namespace, &secondary_namespace, &key);
 		Box::pin(async move { res })
 	}
 	fn write(
 		&self, primary_namespace: &str, secondary_namespace: &str, key: &str, buf: Vec<u8>,
-	) -> Pin<Box<dyn Future<Output = Result<(), io::Error>> + 'static + Send>> {
+	) -> AsyncResult<'static, (), io::Error> {
 		let path = format!("{primary_namespace}/{secondary_namespace}/{key}");
 		let future = Arc::new(Mutex::new((None, None)));
 
@@ -1030,13 +1031,13 @@ impl KVStore for TestStore {
 	}
 	fn remove(
 		&self, primary_namespace: &str, secondary_namespace: &str, key: &str,
-	) -> Pin<Box<dyn Future<Output = Result<(), io::Error>> + 'static + Send>> {
+	) -> AsyncResult<'static, (), io::Error> {
 		let res = self.remove_internal(&primary_namespace, &secondary_namespace, &key);
 		Box::pin(async move { res })
 	}
 	fn list(
 		&self, primary_namespace: &str, secondary_namespace: &str,
-	) -> Pin<Box<dyn Future<Output = Result<Vec<String>, io::Error>> + 'static + Send>> {
+	) -> AsyncResult<'static, Vec<String>, io::Error> {
 		let res = self.list_internal(primary_namespace, secondary_namespace);
 		Box::pin(async move { res })
 	}