ExampleBlocking elapsed-time output varies on Windows #92

The maintainer requested a separate report for Windows test flakiness in #90.

On the rebased PR head 2250d06, running go test -mod=mod -shuffle=on -timeout 60s -coverprofile=round-coverage.txt -covermode=atomic . on Windows failed ExampleBlocking because its elapsed time varied:

got:  Elem 4 received after 2ms
want: Elem 4 received after 1ms

The run reported 100.0% statement coverage but failed due to this example output. This run did not use the race detector; make test-coverage was unavailable because make and a C compiler were not on PATH.