to fix the race of two threads that change mPendingIntent; one assigns a new one
and the other nullifies it.
Change-Id: I5e01f83ea1ac437811d2073839adef9bd0a30ec9
Events are sorted by periods. So events of larger periods may have trigger
time (i.e., when the event should be processed) earlier than the ones of smaller
periods. So need to scan the whole queue looking for due events. The scan takes
O(n) time but we expect the queue size to be small.
Change-Id: I08bd3bd9d4bb8decb78f3c91c943396463ca023a
This is to prepare to move keepalive process to SipSessionGroup before fixing
the following bug.
Bug: 3464181
Change-Id: I57d8f6effad76706b5a76e1269c53d558db88ae4