absenceBudget

How long an absence assertion waits for the frame it expects never to arrive (awaitSilence).

Deliberately not nullable, where awaitBudget is: a wait for something to happen may legitimately be unbounded and lean on runTest's TEST_WEDGE_BACKSTOP, but a wait for nothing to happen that never expires never returns. So a real-I/O subclass that sets awaitBudget to null still gets a terminating absence check — this budget is then real wall-clock rather than virtual, and such a subclass should raise it to whatever its transport's worst-case one-way latency is. Under an in-memory harness it is virtual and free.

What it cannot do is turn absence into proof. "No frame arrived in N" is green when the frame was merely slow, and no value of N fixes that. What makes the absence assertions here load-bearing is not this number but the ordering around them: every one is preceded by a positive control on the same path — a frame that demonstrably did arrive after the one under test was demonstrably dispatched — so the check cannot pass merely by nothing having happened yet. Raising this budget is a latency accommodation, never a strengthening.