/**
* Drains the byte buffer. By default, it decrypts the SSL data and copies as many byte as
* possible to the target buffer, with no modification.
*/
@Override
public int onDrain(Buffer buffer, int maxDrained, Object... args) throws IOException {
ByteBuffer applicationBuffer = (ByteBuffer) args[0];
int initialSize = buffer.remaining();
SSLEngineResult sslResult =
getConnection().getSslEngine().unwrap(buffer.getBytes(), applicationBuffer);
getConnection().setSslResult(sslResult);
return initialSize - buffer.remaining();
}