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.exceptions;
  
  /**
   * Indicates an overflow happened because the upstream disregarded backpressure completely or
   * {@link org.reactivestreams.Subscriber#onNext(Object)} was called concurrently from multiple threads
   * without synchronization. Rarely, it is an indication of bugs inside an operator.
   * @since 3.1.6
   */
  public final class QueueOverflowException extends RuntimeException {
  
      private static final long serialVersionUID = 8517344746016032542L;
  
      /**
       * The message for queue overflows.
       * <p>
       * This can happen if the upstream disregards backpressure completely or calls
       * {@link org.reactivestreams.Subscriber#onNext(Object)} concurrently from multiple threads
       * without synchronization. Rarely, it is an indication of bugs inside an operator.
       */
      private static final String DEFAULT_MESSAGE = "Queue overflow due to illegal concurrent onNext calls or a bug in an operator";
  
      /**
       * Constructs a QueueOverflowException with the default message.
       */
      public QueueOverflowException() {
          this(DEFAULT_MESSAGE);
      }
  
      /**
       * Constructs a QueueOverflowException with the given message but no cause.
       * @param message the error message
       */
      public QueueOverflowException(String message) {
          super(message);
      }
  }
  