:sig
String ws_message()

:params
return value : payload of the current WebSocket message

:see
>websocket

:content
Returns the payload of the current WebSocket message being handled by `WS(Request& context)`.

For text frames this is the decoded text payload. For binary frames this `String` contains the raw message bytes.

Use `ws_is_binary()` or `ws_opcode()` to choose how to parse the payload.

:example
// Inside a WS message handler ws_message() returns the current frame payload.
print("payload length in this non-WS context: ", ws_message().length(), "\n");
