code: func (wc *WhisperClient) SetMaxMessageSize(ctx *Context, size int32) error {
  	return wc.client.SetMaxMessageSize(ctx.context, uint32(size))
  }
docs: // SetMaxMessageSize sets the maximal message size allowed by this node. Incoming
  // and outgoing messages with a larger size will be rejected. Whisper message size
  // can never exceed the limit imposed by the underlying P2P protocol (10 Mb).