Prototype WS support in Tiled

[danielballan]

Our demo client usage is like this:

test-redis-ws/streaming_client.py

Line 61 in a608460

await stream_node('481980', envelope_format="msgpack")

The actual Tiled client has Python objects (tiled.client.base.BaseClient) that represent nodes. Given a client-side object x, something like:

for update in x.stream():
    ...

is probably the simplest API we can offer user code. We should consider:

• What can we learn from httpx stream APIs?
• What can we learn from httpx_ws' API?
• What is the appropriate abstraction level to present to users of Tiled, who want slices of array and partitions of table to feed to scientific code?
• What parameters might this method grow when we switch from /stream/single/{path} to /stream/multi? Will it be possible to manage that transition in a backward-compatible way?

[danielballan]

Note that a pull-based (generator) API is proposed here. Calling x.stream() would provision a WS connection receiving updates on a thread, populating a queue. The generator pops from the queue.