838103616 bytes is 799 MiB (Mebibytes, the power-of-two-based prefix),
which matches GC 13. (Note that the computation for the heap goal just
divides by 1<<20, or 1 MiB.)
The discrepancy in GC count is probably due to the fact that the GC count
value reported by the GC trace is *after* the incr
Might it have something to do with the comment in mgc.go about how the
increment of memstats.numgc differs from the increment of GC cycles for
gctrace? memstats.numgc seems to get incremented earlier (after mark
termination) whereas gctrace waits until the sweep is done.
// cycles is the number
