This is useful in some debugging scenarios. System.err is separately buffered, so when e.g. debugging test cases it doesn't interleave correctly with the C++ stdout/stderr logging. Even using flush() doesn't seem to help, I think because Gradle does its own buffering.
These enable more consistent use of synchronization across the
native libraries. Users can create Event and Semaphore primitives, but
in addition, libraries can set up any handle as an Event-type signal.
