Add an example showing receive side throttling

[jan-ivar]

The API and the underlying QUIC stack mentions that it supports back pressure from the receiver to the sender through ACKs.

From this, one might assume that a receiver may thottle its reception independently for streams it controls, say stream A, B and C.

Q: Does this mean a receiver can throttle reception? I.e. consume C at full speed, but intentionally throttle A and B to give C priority?

If so, should we make this explicit with a use case or an example?

[jan-ivar]

Meeting:

• Mostly yes, the receiver can throttle by not reading. If you don't read from the receive buffer it eventually will become full
• This might affect the browser's flow control window of the individual streams, or other side effects. Browser probably shouldn't be doing this
• An example of consumption at different rates might be worthwhile.
• Might affect other receivers in a pooled connection? That's why we have separate flow control per stream

[jan-ivar]

Rough idea for an example might be:

• Set up two incoming streams A and B. Assume uniform chunk sizes
• pull from B at half the rate of A.
• Tension between something simple and something more useful

[jan-ivar]

Strictly speaking the lack of an example needn't hold up CR.