Earlier, we were using 'send_event' in 'do_update_message'
which can lead to a situation where we enqueue events but
the transaction fails at a later stage.
Events should not be sent until we know we're not rolling back.
This commit updates code, majorly in tests, to use
setting values from enums instead of directly using
the constants defined in Realm.
We still have those constants defined Realm as they
are used in a couple of places where the same code
is used for different settings. These will be
handled later.
Earlier, we were using 'send_event' & 'queue_json_publish' in
'do_send_messages' which can lead to a situation where we enqueue
events but the transaction fails at a later stage.
Events should not be sent until we know we're not rolling back.
For the common case of not needing to reference the UserMessage row
later, and for being a stream without private history, the UserMessage
row is irrelevant. Convert `has_user_message` to a thunk, and defer
loading it unless necessary.
Prakhar Pratyush
Sahil Batra
Alex Vandiver