(iOS only) Count of times that the connection health check is in pending.
The health check counters must not be considered as markers of time.
There is a possible situation in the health check (which calls the
telemetry) which frequently results in more than one count per second.
The situation: A health check is conducted because a network check did not
return, and milliseconds later that network check returns and another
health check is started because of the return.