Improvement: Add user data pointer to AsyncWebSocketClient

[herm]

Often it is required to cache a full websocket message before processing it. This buffer needs to be associated to an individual client to avoid race conditions. Currently I need to use std::map to map the client id to a buffer. It would be faster and easier if there was a void * in AsyncWebSocketClient which could be used for any purpose the user of this library wants.

Many other libraries do the same thing, either providing a pointer to the callback or allowing to store data on the object.

Another option would be a new variant of AsyncWebSocketClient which does the buffering internally and only calls the callback once the message is completely received.

[me-no-dev]

Done ;) use _tempObject for that (the same one exists also for WebRequest)

[herm]

Thank you for the quick response. Just one remark: If this is public API the name should probably start without an underscore.

[me-no-dev]

maybe but it already does in the request class so better have it the same :)