*
   * <ul>
   *   <li>{@code null} initial state, nothing has happened.
   *   <li>{@link Cancellation} terminal state, {@code cancel} was called.
   *   <li>{@link Failure} terminal state, {@code setException} was called.
   *   <li>{@link SetFuture} intermediate state, {@code setFuture} was called.
   *   <li>{@link #NULL} terminal state, {@code set(null)} was called.

   *
   * <ul>
   *   <li>Any {@link ExecutionException} has its <i>cause</i> wrapped in an {@code X} if the cause
   *       is a checked exception, an {@link UncheckedExecutionException} if the cause is a {@code
   *       RuntimeException}, or an {@link ExecutionError} if the cause is an {@code Error}.
   *   <li>Any {@link InterruptedException} is wrapped in an {@code X} (after restoring the

   * }</pre>
   *
   * <p>returns a set containing six lists:
   *
   * <ul>
   *   <li>{@code ImmutableList.of(1, "A")}
   *   <li>{@code ImmutableList.of(1, "B")}
   *   <li>{@code ImmutableList.of(1, "C")}
   *   <li>{@code ImmutableList.of(2, "A")}
   *   <li>{@code ImmutableList.of(2, "B")}
   *   <li>{@code ImmutableList.of(2, "C")}
   * </ul>
   *

        return validateStringNotEmpty(EMPTY, fieldName, problems, severity, version, string, null, tracker);
    }

    /**
     * Asserts:
     * <p/>
     * <ul>
     * <li><code>string != null</code>
     * <li><code>string.length > 0</code>
     * </ul>
     */
    @SuppressWarnings("checkstyle:parameternumber")
    private boolean validateStringNotEmpty(
            String prefix,

	go func() {
		var buf bytes.Buffer
		enc := json.NewEncoder(&buf)
		for {
			select {
			case <-ctx.Done():
				return
			case li := <-logCh:
				if !li.SendLog(node, logKind) {
					continue
				}
				buf.Reset()
				if err := enc.Encode(li); err != nil {
					continue
				}
				select {
				case <-ctx.Done():
					return