Subject: [quicwg/base-drafts] 2c5f8f: Deadlocks, and how to avoid them (#3458)

From: Martin Thomson <[email-masked]>
Date: Tue, 18 Feb 2020 15:13:41 -0800

Branch: refs/heads/master
  Home:   https://github.com/quicwg/base-drafts
  Commit: 2c5f8fcfc00e4b470564dbfc6ac4f9046d98c974
      https://github.com/quicwg/base-drafts/commit/2c5f8fcfc00e4b470564dbfc6ac4f9046d98c974
  Author: Martin Thomson <[email-masked]>
  Date:   2020-02-18 (Tue, 18 Feb 2020)

  Changed paths:
    M draft-ietf-quic-qpack.md

  Log Message:
  -----------
  Deadlocks, and how to avoid them (#3458)

* Deadlocks, and how to avoid them

Much belated, this attempts to address the concerns about deadlocking.
Basically, this says that you should avoid instructions that don't have
flow control credit.  It doesn't say how an encoder might learn what
limits are, but we've seen a range of tactics being used in
implementations and I don't want to get into transport API debates.

This doesn't cover the memory exhaustion attack that @kazuho suggests on
the issue; I think that is better covered more generally by the
connection-level flow control limits.

Closes #1420.

* Taking Ian's suggestion and rearranging slighty