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.operators;
  
  import io.reactivex.rxjava3.annotations.NonNull;
  import io.reactivex.rxjava3.core.FlowableSubscriber;
  
  /**
   * A {@link FlowableSubscriber} with an additional {@link #tryOnNext(Object)} method that
   * tells the caller the specified value has been accepted or not.
   *
   * <p>This allows certain queue-drain or source-drain operators
   * to avoid requesting 1 on behalf of a dropped value.
   *
   * @param <T> the value type
   * @since 3.1.1
   */
  public interface ConditionalSubscriber<@NonNull T> extends FlowableSubscriber<T> {
      /**
       * Conditionally takes the value.
       * @param t the value to deliver
       * @return true if the value has been accepted, false if the value has been rejected
       * and the next value can be sent immediately
       */
      boolean tryOnNext(@NonNull T t);
  }
  