How far ahead of the receiver's clock a reconstructed start may be.
Guards CLOCK SKEW. Transit only ever makes a report older, so a start ahead of
the receiver means the clocks disagree, and the budget is spent by BOTH of
them: a receiver 20 min slow reading a sender 20 min fast sees a 40 min
apparent offset while neither is far off alone. So an hour is about half an
hour of drift per device. A sender whose clock runs consistently fast still
orders its own reports correctly, because a constant offset cancels.
How far ahead of the receiver's clock a reconstructed start may be.
Guards CLOCK SKEW. Transit only ever makes a report older, so a start ahead of the receiver means the clocks disagree, and the budget is spent by BOTH of them: a receiver 20 min slow reading a sender 20 min fast sees a 40 min apparent offset while neither is far off alone. So an hour is about half an hour of drift per device. A sender whose clock runs consistently fast still orders its own reports correctly, because a constant offset cancels.