I’m using asyncio for the first time and find it a bit strange that asyncio.StreamReader.read is async but asyncio.StreamWriter.write is sync. Instead asyncio.StreamWriter.drain is async.
Based on experience with streaming IO in other langs, I’d expect the concrete StreamWriter implementation to notice when its internal buffer is full and flush as necessary. Since any write could trigger that case, I’d expect write to be async and for drain to be something you only call for latency/shutdown reasons. The current design seems to require StreamWriter derived classes to buffer an arbitrary amount of data internally which goes against the goal of being for streaming, where you’re typically trying to stay in memory limits.
Why the asymmetry?