Due to the refcounted nature of Bytes, this allows the stream to avoid taking a copy of the data.
However, note that this function may still perform partial writes, just like write_async. If that occurs, to continue writing, you will need to create a new Bytes containing just the remaining bytes, using Bytes.from_bytes. Passing the same Bytes instance multiple times potentially can result in duplicated data in the output stream.
For the synchronous, blocking version of this function, see write_bytes .
The bytes to write
the io priority of the request.
optional Cancellable object, null to ignore.
callback to call when the request is satisfied
the data to pass to callback function