init: add -txsendrate configuration parameter

diff --git a/src/init.cpp b/src/init.cpp
index 290f0936..4eee0ac5 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -710,6 +710,10 @@ void SetupServerArgs(ArgsManager& argsman, bool can_listen_ipc)
                    OptionsCategory::NODE_RELAY);
     argsman.AddArg("-minrelaytxfee=<amt>", strprintf("Fees (in %s/kvB) smaller than this are considered zero fee for relaying, mining and transaction creation (default: %s)",
         CURRENCY_UNIT, FormatMoney(DEFAULT_MIN_RELAY_TX_FEE)), ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
+    argsman.AddArg("-txsendrate=<n>",
+                   strprintf("Set the maximum ongoing rate for sending transactions to (inbound) peers (default: %u tx/s)",
+                             DEFAULT_TX_SEND_RATE),
+                   ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::NODE_RELAY);
     argsman.AddArg("-privatebroadcast",
                    strprintf(
                        "Broadcast transactions submitted via sendrawtransaction RPC using short-lived "
diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index bc90b0c5..56c79c2c 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -168,11 +168,6 @@ static constexpr auto INBOUND_INVENTORY_BROADCAST_INTERVAL{5s};
  *  Use a smaller delay as there is less privacy concern for them.
  *  Blocks and peers with NetPermissionFlags::NoBan permission bypass this. */
 static constexpr auto OUTBOUND_INVENTORY_BROADCAST_INTERVAL{2s};
-/** Maximum rate of inventory items to send per second.
- *  Limits the impact of low-fee transaction floods. */
-[[maybe_unused]] static constexpr unsigned int INVENTORY_BROADCAST_PER_SECOND{14};
-/** Target number of tx inventory items to send per transmission. */
-[[maybe_unused]] static constexpr unsigned int INVENTORY_BROADCAST_TARGET = INVENTORY_BROADCAST_PER_SECOND * count_seconds(INBOUND_INVENTORY_BROADCAST_INTERVAL);
 /** Multiplier for the inventory bucket rate for outbounds */
 static constexpr double OUTBOUND_INVENTORY_BUCKET_MULTIPLIER{Ticks<SecondsDouble>(INBOUND_INVENTORY_BROADCAST_INTERVAL) / Ticks<SecondsDouble>(OUTBOUND_INVENTORY_BROADCAST_INTERVAL)};
 /** Delay between checking inventory bucket and backlog */
@@ -531,7 +526,7 @@ struct InvToSendBucket {
     static constexpr double INBOUND_COUNT_SECONDS{30}; // cap/initial at 30s/mult worth of txs
 
     InvToSendBucket(unsigned int rate, double mult)
-        : count_floor{-1.0 * INVENTORY_BROADCAST_TARGET},
+        : count_floor{-1.0 * rate * count_seconds(INBOUND_INVENTORY_BROADCAST_INTERVAL)},
           size_bucket(/*rate=*/SIZE_REFILL * mult, /*value=*/SIZE_INIT, /*cap=*/SIZE_CAP),
           count_bucket(/*rate=*/rate * mult, /*value=*/rate * INBOUND_COUNT_SECONDS, /*cap=*/rate * INBOUND_COUNT_SECONDS)
     {
@@ -2112,8 +2107,8 @@ PeerManagerImpl::PeerManagerImpl(CConnman& connman, AddrMan& addrman,
       m_txdownloadman(node::TxDownloadOptions{pool, m_rng, opts.deterministic_rng}),
       m_warnings{warnings},
       m_opts{opts},
-      m_inbound_inv_bucket(/*rate=*/INVENTORY_BROADCAST_PER_SECOND, /*mult=*/1.0),
-      m_outbound_inv_bucket(/*rate=*/INVENTORY_BROADCAST_PER_SECOND, /*mult=*/OUTBOUND_INVENTORY_BUCKET_MULTIPLIER)
+      m_inbound_inv_bucket(/*rate=*/m_opts.tx_send_rate, /*mult=*/1.0),
+      m_outbound_inv_bucket(/*rate=*/m_opts.tx_send_rate, /*mult=*/OUTBOUND_INVENTORY_BUCKET_MULTIPLIER)
 {
     // While Erlay support is incomplete, it must be enabled explicitly via -txreconciliation.
     // This argument can go away after Erlay support is complete.
diff --git a/src/net_processing.h b/src/net_processing.h
index f29adc01..8e6c4b87 100644
--- a/src/net_processing.h
+++ b/src/net_processing.h
@@ -42,6 +42,8 @@ static constexpr bool DEFAULT_TXRECONCILIATION_ENABLE{false};
 /** Default number of non-mempool transactions to keep around for block reconstruction. Includes
     orphan, replaced, and rejected transactions. */
 static const uint32_t DEFAULT_BLOCK_RECONSTRUCTION_EXTRA_TXN{100};
+/** Default maximum per-second rate for sending transaction inventory to peers. */
+static constexpr unsigned int DEFAULT_TX_SEND_RATE{14};
 static const bool DEFAULT_PEERBLOOMFILTERS = false;
 static const bool DEFAULT_PEERBLOCKFILTERS = false;
 /** Maximum number of outstanding CMPCTBLOCK requests for the same block. */
@@ -96,6 +98,8 @@ public:
         uint32_t max_headers_result{MAX_HEADERS_RESULTS};
         //! Whether private broadcast is used for sending transactions.
         bool private_broadcast{DEFAULT_PRIVATE_BROADCAST};
+        //! Maximum per-second rate for sending transaction inventory to peers.
+        unsigned int tx_send_rate{DEFAULT_TX_SEND_RATE};
     };
 
     static std::unique_ptr<PeerManager> make(CConnman& connman, AddrMan& addrman,
diff --git a/src/node/peerman_args.cpp b/src/node/peerman_args.cpp
index 9745d69d..47413af0 100644
--- a/src/node/peerman_args.cpp
+++ b/src/node/peerman_args.cpp
@@ -24,6 +24,10 @@ void ApplyArgsManOptions(const ArgsManager& argsman, PeerManager::Options& optio
 
     if (auto value{argsman.GetBoolArg("-blocksonly")}) options.ignore_incoming_txs = *value;
 
+    if (auto value{argsman.GetIntArg("-txsendrate")}) {
+        options.tx_send_rate = uint32_t(std::clamp<int64_t>(*value, 1, 1000));
+    }
+
     if (auto value{argsman.GetBoolArg("-privatebroadcast")}) options.private_broadcast = *value;
 }
 
diff --git a/src/node/txdownloadman.h b/src/node/txdownloadman.h
index 2cc1ec2c..bef1d162 100644
--- a/src/node/txdownloadman.h
+++ b/src/node/txdownloadman.h
@@ -25,7 +25,7 @@ class TxDownloadManagerImpl;
 static constexpr int32_t MAX_PEER_TX_REQUEST_IN_FLIGHT = 100;
 /** Maximum number of transactions to consider for requesting, per peer. It provides a reasonable DoS limit to
  *  per-peer memory usage spent on announcements, while covering peers continuously sending INVs at the maximum
- *  rate (by our own policy, see INVENTORY_BROADCAST_PER_SECOND) for several minutes, while not receiving
+ *  rate (by our own policy, see DEFAULT_TX_SEND_RATE) for several minutes, while not receiving
  *  the actual transaction (from any peer) in response to requests for them. */
 static constexpr int32_t MAX_PEER_TX_ANNOUNCEMENTS = 5000;
 /** How long to delay requesting transactions via txids, if we have wtxid-relaying peers */