The push effect re-runs every time a login connects, which while a browser
with many logins restores means once per account. Each run closed every
client's push and set it up again: the live streams were torn down and
reopened and every slow poll re-primed its baseline with a full state read
(Mailbox, Email, Calendar, CalendarEvent, SieveScript) - quadratic in the
number of accounts. With ten logins that was 21 stream openings and about
180 state-poll methods in the first seconds.
Reconcile instead: bind the clients that are new, unbind the ones that are
gone, and on an account switch re-bind only the two logins whose role
changed, handing the live stream to the newly active one when it has
none. Handlers are read through a ref at event time, so a binding never has
to be re-created because a callback changed identity.
The reconciliation is a pure function (lib/push-bindings.ts) with its own
tests; the effect only supplies the callbacks.
Linus Rath
lucamzanon