add a comment for MConnection#CanSend

also add a note to TestMConnectionSend

connection.go

@@ -258,6 +258,8 @@ func (c *MConnection) TrySend(chID byte, msg interface{}) bool {
 	return ok
 }
 
+// CanSend returns true if you can send more data onto the chID, false
+// otherwise. Use only as a heuristic.
 func (c *MConnection) CanSend(chID byte) bool {
 	if !c.IsRunning() {
 		return false

connection_test.go

@@ -37,9 +37,9 @@ func TestMConnectionSend(t *testing.T) {
 
 	msg := "Ant-Man"
 	assert.True(mconn.Send(0x01, msg))
+	// Note: subsequent Send/TrySend calls could pass because we are reading from
+	// the send queue in a separate goroutine.
 	assert.False(mconn.CanSend(0x01), "CanSend should return false because queue is full")
-	// assert.False(mconn.Send(0x01, msg), "Send should return false because queue is full")
-	// assert.False(mconn.TrySend(0x01, msg), "TrySend should return false because queue is full")
 	server.Read(make([]byte, len(msg)))
 	assert.True(mconn.CanSend(0x01))