Create Stream description lacks option for "Stream already exists"

[tulshi]

If a Transmitter wanted to support only one stream between itself and a specific Receiver, then the Transmitter should have a way to respond to a Receiver that has already created a stream with a status 303 (see other) or some such way of indicating that a stream already exists.

[ptravers]

I would suggest returning 200 with the previously created entity. then return 201 if the stream did not already exist when create is called

[timcappalli]

There is precedent for @ptravers recommendation in the SCIM core protocol

If the resource exists, the server responds with HTTP status code 200 (OK) and includes the result in the body of the response.

on 2023-03-21 call, consensus to follow this approach.