code: @CheckReturnValue
      @NonNull
      public static <T> ReplayRelay<T> create() {
          return new ReplayRelay<T>(new UnboundedReplayBuffer<T>(16));
      }
docs: Creates an unbounded replay relay.
  <p>
  The internal buffer is backed by an {@link ArrayList} and starts with an initial capacity of 16. Once the
  number of items reaches this capacity, it will grow as necessary (usually by 50%). However, as the
  number of items grows, this causes frequent array reallocation and copying, and may hurt performance
  and latency. This can be avoided with the {@link #create(int)} overload which takes an initial capacity
  parameter and can be tuned to reduce the array reallocation frequency as needed.