net: Cache -capturemessages setting

diff --git a/src/init.cpp b/src/init.cpp
index bfb9483a..4acd729b 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -2043,6 +2043,7 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
     connOptions.m_peer_connect_timeout = peer_connect_timeout;
     connOptions.whitelist_forcerelay = args.GetBoolArg("-whitelistforcerelay", DEFAULT_WHITELISTFORCERELAY);
     connOptions.whitelist_relay = args.GetBoolArg("-whitelistrelay", DEFAULT_WHITELISTRELAY);
+    connOptions.m_capture_messages = args.GetBoolArg("-capturemessages", false);
 
     // Port to bind to if `-bind=addr` is provided without a `:port` suffix.
     const uint16_t default_bind_port =
diff --git a/src/net.cpp b/src/net.cpp
index a6e115b2..faa6710d 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -3901,7 +3901,7 @@ void CConnman::PushMessage(CNode* pnode, CSerializedNetMsg&& msg)
     AssertLockNotHeld(m_total_bytes_sent_mutex);
     size_t nMessageSize = msg.data.size();
     LogDebug(BCLog::NET, "sending %s (%d bytes) peer=%d\n", msg.m_type, nMessageSize, pnode->GetId());
-    if (gArgs.GetBoolArg("-capturemessages", false)) {
+    if (m_capture_messages) {
         CaptureMessage(pnode->addr, msg.m_type, msg.data, /*is_incoming=*/false);
     }
 
diff --git a/src/net.h b/src/net.h
index 387a8c06..eedfdfaf 100644
--- a/src/net.h
+++ b/src/net.h
@@ -1086,6 +1086,7 @@ public:
         bool m_i2p_accept_incoming;
         bool whitelist_forcerelay = DEFAULT_WHITELISTFORCERELAY;
         bool whitelist_relay = DEFAULT_WHITELISTRELAY;
+        bool m_capture_messages = false;
     };
 
     void Init(const Options& connOptions) EXCLUSIVE_LOCKS_REQUIRED(!m_added_nodes_mutex, !m_total_bytes_sent_mutex)
@@ -1123,8 +1124,12 @@ public:
         m_onion_binds = connOptions.onion_binds;
         whitelist_forcerelay = connOptions.whitelist_forcerelay;
         whitelist_relay = connOptions.whitelist_relay;
+        m_capture_messages = connOptions.m_capture_messages;
     }
 
+    // test only
+    void SetCaptureMessages(bool cap) { m_capture_messages = cap; }
+
     CConnman(uint64_t seed0,
              uint64_t seed1,
              AddrMan& addrman,
@@ -1666,6 +1671,11 @@ private:
      */
     bool whitelist_relay;
 
+    /**
+     * flag for whether messages are captured
+     */
+    bool m_capture_messages{false};
+
     /**
      * Mutex protecting m_i2p_sam_sessions.
      */
diff --git a/src/test/net_tests.cpp b/src/test/net_tests.cpp
index a2ff9a10..aea29169 100644
--- a/src/test/net_tests.cpp
+++ b/src/test/net_tests.cpp
@@ -814,7 +814,7 @@ BOOST_AUTO_TEST_CASE(initial_advertise_from_version_message)
     // Pretend that we bound to this port.
     const uint16_t bind_port = 20001;
     m_node.args->ForceSetArg("-bind", strprintf("3.4.5.6:%u", bind_port));
-    m_node.args->ForceSetArg("-capturemessages", "1");
+    m_node.connman->SetCaptureMessages(true);
 
     // Our address:port as seen from the peer - 2.3.4.5:20002 (different from the above).
     in_addr peer_us_addr;
@@ -892,7 +892,7 @@ BOOST_AUTO_TEST_CASE(initial_advertise_from_version_message)
 
     CaptureMessage = CaptureMessageOrig;
     chainman.ResetIbd();
-    m_node.args->ForceSetArg("-capturemessages", "0");
+    m_node.connman->SetCaptureMessages(false);
     m_node.args->ForceSetArg("-bind", "");
 }