add method Null safety
data to the target consumer, ignoring encoding.
The encoding does not apply to this method, and the
data list is passed
directly to the target consumer as a stream event.
This function must not be called when a stream is currently being added using addStream.
This operation is non-blocking. See flush or done for how to get any errors generated by this call.
The data list should not be modified after it has been passed to
void add(List<int> data);