net: note CNode members that are treated as const

m_permissionFlags and m_prefer_evict are treated as const -- they're
only set immediately after construction before any other thread has
access to the object, and not changed again afterwards. As such they
don't need to be marked atomic or guarded by a mutex; though it would
probably be better to actually mark them as const...

Author: ajtowns

src/net.h

@@ -344,7 +344,7 @@ class CNode
     const std::unique_ptr<TransportDeserializer> m_deserializer; // Used only by SocketHandler thread
     const std::unique_ptr<const TransportSerializer> m_serializer;
 
-    NetPermissionFlags m_permissionFlags{NetPermissionFlags::None};
+    NetPermissionFlags m_permissionFlags{NetPermissionFlags::None}; // treated as const outside of fuzz tester
 
     /**
      * Socket used for communication with the node.
@@ -393,7 +393,7 @@ class CNode
      * from the wire. This cleaned string can safely be logged or displayed.
      */
     std::string cleanSubVer GUARDED_BY(m_subver_mutex){};
-    bool m_prefer_evict{false}; // This peer is preferred for eviction.
+    bool m_prefer_evict{false}; // This peer is preferred for eviction. (treated as const)
     bool HasPermission(NetPermissionFlags permission) const {
         return NetPermissions::HasFlag(m_permissionFlags, permission);
     }