upload Base64File
Uploads a base64-encoded file and returns its URL.
Requires a joined room: the upload address is part of the server configuration fetched while joining.
Throws
code 3073 (ERROR_INVALID_PARAMETER) if any argument is empty, 3035 / 3065 if the room is not joined or is reconnecting, or 3074 (ERROR_FILE_UPLOAD_FAILED) when the request cannot be sent or the server answers with an error status, the message naming it. That failure also reaches RoomEventListener.onError.