code: /*
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.rxjava3.internal.fuseable;
  
  import io.reactivex.rxjava3.annotations.NonNull;
  import io.reactivex.rxjava3.core.MaybeSource;
  
  /**
   * Interface indicating the implementor has an upstream MaybeSource-like source available
   * via {@link #source()} method.
   *
   * @param <T> the value type
   */
  public interface HasUpstreamMaybeSource<@NonNull T> {
      /**
       * Returns the upstream source of this Maybe.
       * <p>Allows discovering the chain of observables.
       * @return the source MaybeSource
       */
      @NonNull
      MaybeSource<T> source();
  }
  