This test keeps failing on macOS CI,
capturing events like `DC_EVENT_ACCOUNTS_ITEM_CHANGED`
before FailPlugin is setup.
These CI runners likely get less resources
because there is a limited number of them,
and this triggers this race condition.
Race is fixed by setting up fail plugin
before starting to capture events.
We already synchronise status/footer when we see a self-sent message with a Chat-Version
header. Would be nice to do the same for display name.
But let's do it the same way as for `Config::{MdnsEnabled,ShowEmails}`. Otherwise, if we sync the
display name using the "From" header, smth like `Param::StatusTimestamp` is needed then to reject
outdated display names. Also this timestamp needs to be updated when `Config::Displayname` is set
locally. Also this wouldn't work if system time isn't synchronised on devices. Also using multiple
approaches to sync different config values would lead to more code and bugs while having almost no
value -- using "From" only saves some bytes and allows to sync some things w/o the synchronisation
itself to be enabled. But the latter also can be a downside -- if it's usual synchonisation, you can
(potentially) disable it and share the same email account across people in some organisation
allowing them to have different display names. With using "From" for synchronisation such a
capability definitely requires a new config option.
Opening the same account (context) from multiple processes is dangerous, can result in duplicate
downloads of the same message etc. Same for account manager, attempts to modify the same
accounts.toml even if done atomically with may result in corrupted files as atomic replacement
procedure does not expect that multiple processes may write to the same temporary file.
accounts.toml cannot be used as a lockfile because it is replaced during atomic update. Therefore, a
new file next to accounts.toml is needed to prevent starting second account manager in the same
directory.
But iOS needs to be able to open accounts from multiple processes at the same time. This is required
as the "share-to-DC extension" is a separate process by iOS design -- this process may or may not be
started while the main app is running. Accounts are not altered however by this extension, so let's
add to the `Accounts::new()` constructor an `rdwr` parameter which allows to read the accounts
config w/o locking the lockfile.
