The reader and the writer now communicate through a channel and the packet
cache.  If the writer thread drops behind, we drop packets after inserting in
the packet cache, which avoids building a backlog.

For now, this is only used to request screen sharing as opposed to normal
videos.  In the future, it will be used for simulcasting.

Commit 8257a7ff "Remove dead variables." was wrong in that it deleted
the 'diconnect' [sic] variable definition, and left the
'disconnectbutton' variable undefined.

I'm an idiot.

We used to deadlock with large numbers of tracks.  This should fix that.

Thanks to Antonin Décimo.

> Rejeté. Ce n'est pas un escape.

D’après mes tests, c’est considéré comme un escape. Doubler le
caractère serait suffisant.

    const url = 'https://example\\.com';
    const urlRegexp1 = /https?:\/\/[-a-zA-Z0-9@:%/._\+~#=?]+[-a-zA-Z0-9@:%/_\+~#=]/g;
    const urlRegexp2 = /https?:\/\/[-a-zA-Z0-9@:%/._\\+~#=?]+[-a-zA-Z0-9@:%/_\\+~#=]/g;
    console.log(url.length); // 20
    console.log(urlRegexp1.exec(url)); // ["https://example"]
    console.log(urlRegexp2.exec(url)); // ["https://example\.com"]

https://eslint.org/docs/rules/no-unsafe-negation

The previous value caused statistics to occasionally timeout spuriously.

We're closing and reopening the connection each time, we should be
renegotiating instead.

That would be racy.

Don't take packet loss into account, just clamp at 384kbps.