:sig
bool ws_is_binary()

:params
return value : true if the current WebSocket message is binary

:see
>websocket

:content
Returns whether the message currently being handled by `WS(Request& context)` arrived as a binary frame.

If this returns `false`, the current message was delivered as a text frame.

:example
print("ws_is_binary is resource-bound; configure the service or connection, then call it in request code.\n");