Converts the given external_target clock time to the internal time, using the passed calibration parameters. This function performs the same calculation as Clock.unadjustUnlocked when called using the current calibration parameters.
Note: The clock parameter is unused and can be NULL
a clock time
a reference internal time
a reference external time
the numerator of the rate of the clock relative to its internal time
the denominator of the rate of the clock
the converted time of the clock.