Didn't help much. Benchmarks:

begin+end 1:
the code took:307 wallclock secs (109.22 usr + 35.47 sys = 144.69 CPU)

begin+end 2:
the code took:279 wallclock secs (107.95 usr + 37.08 sys = 145.03 CPU)

begin_work+commit:
the code took:297 wallclock secs (107.45 usr + 37.13 sys = 144.58 CPU)
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