tracing: Tracepoints for in- and outbound P2P msgs

Can be used to monitor in- and outbound node traffic.

Based on ealier work by jb55.

Co-authored-by: William Casarin <jb55@jb55.com>

src/net_processing.cpp

@@ -34,6 +34,7 @@
 #include <util/check.h> // For NDEBUG compile time check
 #include <util/strencodings.h>
 #include <util/system.h>
+#include <util/trace.h>
 #include <validation.h>
 
 #include <algorithm>
@@ -4052,6 +4053,15 @@ bool PeerManagerImpl::ProcessMessages(CNode* pfrom, std::atomic<bool>& interrupt
     }
     CNetMessage& msg(msgs.front());
 
+    TRACE6(net, inbound_message,
+        pfrom->GetId(),
+        pfrom->GetAddrName().c_str(),
+        pfrom->ConnectionTypeAsString().c_str(),
+        msg.m_command.c_str(),
+        msg.m_recv.size(),
+        msg.m_recv.data()
+    );
+
     if (gArgs.GetBoolArg("-capturemessages", false)) {
         CaptureMessage(pfrom->addr, msg.m_command, MakeUCharSpan(msg.m_recv), /* incoming */ true);
     }