add some function comments

HubConnection.go

@@ -30,6 +30,7 @@ type HubConnection struct {
 	autoReconnect bool
 }
 
+// Thread-safe user accessor.
 func (this *HubConnection) Users(cb func(*map[string]UserInfo) error) error {
 	this.userLock.Lock()
 	defer this.userLock.Unlock()
@@ -88,6 +89,8 @@ func (this *HubConnection) userJoined_Full(uinf *UserInfo) {
 	}
 }
 
+// SayRaw sends raw bytes over the TCP socket. Callers should add the protocol
+// terminating character `|` themselves.
 // Note that protocol messages are transmitted on the caller thread, not from
 // any internal libnmdc thread.
 func (this *HubConnection) SayRaw(protocolCommand string) error {