public synchronized void resume() {
        final boolean didChange = isPaused.compareAndSet(true, false);
        if (didChange) {
            pauseSemaphore.release(threadCount);
            LOGGER.info(() -> LogUtil.message(
                    "Resumed parallel executor '{}', threadCount: {}, availablePermits: {}",
                    threadNamePrefix, threadCount, pauseSemaphore.availablePermits()));
        }
    }
Immediately resume all the executor's threads if it is currently paused.
If already resumed, is a noop.
stroom-proxy/stroom-proxy-repo/src/main/java/stroom/proxy/repo/ParallelExecutor.java