Method shutdown

src/main/java/groovy/concurrent/Agent.java:205–223

Shuts down the agent's update executor. No further updates will be accepted. Pending updates are executed before shutdown completes. The changes publisher (if any subscribers attached) is closed after pending updates drain, signalling onComplete to all live subscribers. Calling {@code shutdo

()

     * subscribers. Calling {@code shutdown()} more than once is a no-op.
     */
    public void shutdown() {
        SubmissionPublisher<T> p;
        synchronized (lifecycleLock) {
            if (shutdownInvoked) return;
            shutdownInvoked = true;
            p = changesPublisher;
        }
        if (p != null) {
            // Submit close as a terminator task so it runs after any queued
            // updates have drained — ensures applyUpdate never offers to a
            // publisher that has already been closed.
            try {
                updateExecutor.execute(p::close);
            } catch (RejectedExecutionException ex) {
                p.close();
            }
        }
        updateExecutor.shutdown();
    }

    /**
     * Returns a {@link Flow.Publisher} that emits the agent's value after