code: static Node.Builder.OfLong longBuilder(long exactSizeIfKnown) {
          return (exactSizeIfKnown >= 0 && exactSizeIfKnown < MAX_ARRAY_SIZE)
                 ? new LongFixedNodeBuilder(exactSizeIfKnown)
                 : longBuilder();
      }
docs: Produces a {@link Node.Builder.OfLong}.
  
  @param exactSizeIfKnown -1 if a variable size builder is requested,
  otherwise the exact capacity desired.  A fixed capacity builder will
  fail if the wrong number of elements are added to the builder.
  @return a {@code Node.Builder.OfLong}