queueSize

Returns the size in bytes of all messages enqueued to be transmitted to the server. This doesn't include framing overhead. If compression is enabled, uncompressed messages size is used to calculate this value. It also doesn't include any bytes buffered by the operating system or network intermediaries. This method returns 0 if no messages are waiting in the queue. If may return a nonzero value after the web socket has been canceled; this indicates that enqueued messages were not transmitted.

Use this to monitor backpressure and avoid exceeding the 16 MiB outgoing message buffer limit. When that limit is exceeded, the web socket is gracefully shut down.