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.operators.mixed;
  
  import org.reactivestreams.*;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.functions.Function;
  import io.reactivex.rxjava3.internal.operators.mixed.FlowableConcatMapMaybe.ConcatMapMaybeSubscriber;
  import io.reactivex.rxjava3.internal.util.ErrorMode;
  
  /**
   * Maps each upstream item into a {@link MaybeSource}, subscribes to them one after the other terminates
   * and relays their success values, optionally delaying any errors till the main and inner sources
   * terminate.
   * <p>History: 2.1.11 - experimental
   * @param <T> the upstream element type
   * @param <R> the output element type
   * @since 2.2
   */
  public final class FlowableConcatMapMaybePublisher<T, R> extends Flowable<R> {
  
      final Publisher<T> source;
  
      final Function<? super T, ? extends MaybeSource<? extends R>> mapper;
  
      final ErrorMode errorMode;
  
      final int prefetch;
  
      public FlowableConcatMapMaybePublisher(Publisher<T> source,
              Function<? super T, ? extends MaybeSource<? extends R>> mapper,
                      ErrorMode errorMode, int prefetch) {
          this.source = source;
          this.mapper = mapper;
          this.errorMode = errorMode;
          this.prefetch = prefetch;
      }
  
      @Override
      protected void subscribeActual(Subscriber<? super R> s) {
          source.subscribe(new ConcatMapMaybeSubscriber<>(s, mapper, prefetch, errorMode));
      }
  }
  