Let's just call `getrusage` once on each logcontext change, rather than twice.

Only run one background update at a time

By running this stuff with `run_in_background`, it won't be correctly reported
against the relevant CPU usage stats.

Fixes #7202

This reverts commit 0122ef10.

This reverts commit 8d4cbdea.

Synapse 1.12.3 (2020-04-03)
===========================

- Remove the the pin to Pillow 7.0 which was introduced in Synapse 1.12.2, and
correctly fix the issue with building the Debian packages. ([\#7212](https://github.com/matrix-org/synapse/issues/7212))

Synapse 1.12.2 (2020-04-02)
===========================

This release fixes [an
issue](https://github.com/matrix-org/synapse/issues/7208) with building the
debian packages.

No other significant changes since 1.12.1.

This was incorrectly merged to master.

This reverts commit 319c41f5, reversing
changes made to 229eb814.

This was incorrectly merged to `master` instead of develop.

This reverts commit 90246344.

Occasionally we could get a federation device list update transaction which
looked like:

```
[
    {'edu_type': 'm.device_list_update', 'content': {'user_id': '@user:test', 'device_id': 'D2', 'prev_id': [], 'stream_id': 12, 'deleted': True}},
    {'edu_type': 'm.device_list_update', 'content': {'user_id': '@user:test', 'device_id': 'D1', 'prev_id': [12], 'stream_id': 11, 'deleted': True}},
    {'edu_type': 'm.device_list_update', 'content': {'user_id': '@user:test', 'device_id': 'D3', 'prev_id': [11], 'stream_id': 13, 'deleted': True}}
]
```

Having `stream_ids` which are lower than `prev_ids` looks odd. It might work
(I'm not actually sure), but in any case it doesn't seem like a reasonable
thing to expect other implementations to support.

* master:
  1.12.1
  Note where bugs were introduced
  1.12.1rc1
  Newsfile
  Rewrite changelog
  Add changelog
  Only import sqlite3 when type checking
  Fix another instance
  Only setdefault for signatures if device has key_json
  Fix starting workers when federation sending not split out.
  Attempt to clarify Python version requirements (#7161)
  Improve the UX of the login fallback when using SSO (#7152)
  Update the wording of the config comment
  Lint
  Changelog
  Regenerate sample config
  Whitelist the login fallback by default for SSO

Synapse 1.12.1 (2020-04-02)
===========================

No significant changes since 1.12.1rc1.

Synapse 1.12.1rc1 (2020-03-31)
==============================

Bugfixes
--------

- Fix starting workers when federation sending not split out. ([\#7133](https://github.com/matrix-org/synapse/issues/7133)). Introduced in v1.12.0.
- Avoid importing `sqlite3` when using the postgres backend. Contributed by David Vo. ([\#7155](https://github.com/matrix-org/synapse/issues/7155)). Introduced in v1.12.0rc1.
- Fix a bug which could cause outbound federation traffic to stop working if a client uploaded an incorrect e2e device signature. ([\#7177](https://github.com/matrix-org/synapse/issues/7177)). Introduced in v1.11.0.

* tag 'v1.12.1':
  1.12.1
  Note where bugs were introduced
  1.12.1rc1
  Newsfile
  Rewrite changelog
  Add changelog
  Only import sqlite3 when type checking
  Fix another instance
  Only setdefault for signatures if device has key_json
  Fix starting workers when federation sending not split out.

This broke in a recent PR (#7024) and is no longer useful due to all
replication clients implicitly subscribing to all streams, so let's
just remove it.

returning a None or an int that we don't use is confusing.

This mostly just reduces the amount of "running from sentinel context" spam
during unittest setup.

(Almost) everywhere that uses it is happy with an awaitable.

This was only used in a unit test, so let's just inline it in the test.

Fixes #7179.

Signed-off-by: Karl Linderhed <git@karlinde.se>