code: public P get() {
      try {
        return getAsync().join();
      } catch (Exception e) {
        if (e instanceof CompletionException && e.getCause() instanceof RuntimeException) {
          throw (RuntimeException) e.getCause();
        } else {
          throw e;
        }
      }
    }
docs: Gets or builds a singleton instance of the primitive.
  <p>
  The returned primitive will be shared by all {@code get()} calls for the named primitive. If no instance has yet
  been constructed, the instance will be built from this builder's configuration.
  
  @return a singleton instance of the primitive