* <i>happen-before</i></a> its execution begins, perhaps in another thread.
   *
   * <p>Guava implementations of {@code ListenableFuture} promptly release references to listeners
   * after executing them.
   *
   * @param listener the listener to run when the computation is complete
   * @param executor the executor to run the listener in

   * propagate cancellation) and {@link #toString()}. To access the futures' <i>values</i>, {@code
   * AggregateFuture} attaches listeners that hold references to one or more inputs. And in the case
   * of {@link CombinedFuture}, the user-supplied callback usually has its own references to inputs.
   */
  /*
   * In certain circumstances, this field might theoretically not be visible to an afterDone() call

        "The user must change his password before he logs on the first time.", "The object was not found.",
        "The referenced account is currently locked out and may not be logged on to.", "Connection refused",
        "The remote system is not reachable by the transport.", "The layered file system driver for this I/O tag did not handle it when needed.",

  }

  /**
   * Returns a new {@code MutableClassToInstanceMap} instance backed by a given empty {@code
   * backingMap}. The caller surrenders control of the backing map, and thus should not allow any
   * direct references to it to remain accessible.
   */
  public static <B extends @Nullable Object> MutableClassToInstanceMap<B> create(
      Map<Class<? extends @NonNull B>, B> backingMap) {
    return new MutableClassToInstanceMap<>(backingMap);

    /**
     * Append formatted content to the buffer.
     * @see String#format(String, Object...)
     *
     * @param pattern a <a href="../util/Formatter.html#syntax">format string</a>
     * @param args arguments referenced by the format specifiers in the format string
     * @return the current builder
     */
    @Nonnull
    default MessageBuilder format(String pattern, Object... args) {

   * use the {@code HashMap} constructor directly, taking advantage of <a
   * href="https://docs.oracle.com/javase/tutorial/java/generics/genTypeInference.html#type-inference-instantiation">"diamond"
   * syntax</a>.
   *
   * @return a new, empty {@code HashMap}
   */
  @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call

   * use the {@code HashMap} constructor directly, taking advantage of <a
   * href="https://docs.oracle.com/javase/tutorial/java/generics/genTypeInference.html#type-inference-instantiation">"diamond"
   * syntax</a>.
   *
   * @return a new, empty {@code HashMap}
   */
  @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call

        "The user must change his password before he logs on the first time.",
        "NT_STATUS_NOT_FOUND",
        "The referenced account is currently locked out and may not be logged on to.",
        "The remote system is not reachable by the transport.",
        "NT_STATUS_IO_REPARSE_TAG_NOT_HANDLED",
    };

   * <i>happen-before</i></a> its execution begins, perhaps in another thread.
   *
   * <p>Guava implementations of {@code ListenableFuture} promptly release references to listeners
   * after executing them.
   *
   * @param listener the listener to run when the computation is complete
   * @param executor the executor to run the listener in

   * <i>happen-before</i></a> its execution begins, perhaps in another thread.
   *
   * <p>Guava implementations of {@code ListenableFuture} promptly release references to listeners
   * after executing them.
   *
   * @param listener the listener to run when the computation is complete
   * @param executor the executor to run the listener in