code: @Nullable
      public static <T> TtlCallable<T> get(@Nullable Callable<T> callable, boolean releaseTtlValueReferenceAfterCall) {
          return get(callable, releaseTtlValueReferenceAfterCall, false);
      }
docs: Factory method, wrap input {@link Callable} to {@link TtlCallable}.
  <p>
  This method is idempotent.
  
  @param callable                          input {@link Callable}
  @param releaseTtlValueReferenceAfterCall release TTL value reference after run, avoid memory leak even if {@link TtlRunnable} is referred.
  @return Wrapped {@link Callable}