refactor: Initialize magic bytes in constructor initializer

Also remove an assert that is already enforced by the compiler checking
that the length of the std::array matches.

src/net.cpp

@@ -684,10 +684,8 @@ bool CNode::ReceiveMsgBytes(Span<const uint8_t> msg_bytes, bool& complete)
 }
 
 V1Transport::V1Transport(const NodeId node_id, int nTypeIn, int nVersionIn) noexcept :
-    m_node_id(node_id), hdrbuf(nTypeIn, nVersionIn), vRecv(nTypeIn, nVersionIn)
+    m_magic_bytes{Params().MessageStart()}, m_node_id(node_id), hdrbuf(nTypeIn, nVersionIn), vRecv(nTypeIn, nVersionIn)
 {
-    assert(std::size(Params().MessageStart()) == std::size(m_magic_bytes));
-    m_magic_bytes = Params().MessageStart();
     LOCK(m_recv_mutex);
     Reset();
 }

src/net.h

@@ -372,7 +372,7 @@ public:
 class V1Transport final : public Transport
 {
 private:
-    MessageStartChars m_magic_bytes;
+    const MessageStartChars m_magic_bytes;
     const NodeId m_node_id; // Only for logging
     mutable Mutex m_recv_mutex; //!< Lock for receive state
     mutable CHash256 hasher GUARDED_BY(m_recv_mutex);

src/protocol.cpp

@@ -91,9 +91,8 @@ const static std::vector<std::string> g_all_net_message_types{
 };
 
 CMessageHeader::CMessageHeader(const MessageStartChars& pchMessageStartIn, const char* pszCommand, unsigned int nMessageSizeIn)
+    : pchMessageStart{pchMessageStartIn}
 {
-    pchMessageStart = pchMessageStartIn;
-
     // Copy the command name
     size_t i = 0;
     for (; i < COMMAND_SIZE && pszCommand[i] != 0; ++i) pchCommand[i] = pszCommand[i];