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.annotations;
  
  import java.lang.annotation.*;
  
  import io.reactivex.rxjava3.schedulers.Schedulers;
  
  /**
   * Indicates what kind of scheduler the class or method uses.
   * <p>
   * Constants are provided for instances from {@link Schedulers} as well as values for
   * {@linkplain #NONE not using a scheduler} and {@linkplain #CUSTOM a manually-specified scheduler}.
   * Libraries providing their own values should namespace them with their base package name followed
   * by a colon ({@code :}) and then a human-readable name (e.g., {@code com.example:ui-thread}).
   * @since 2.0
   */
  @Retention(RetentionPolicy.RUNTIME)
  @Documented
  @Target({ElementType.CONSTRUCTOR, ElementType.METHOD, ElementType.TYPE})
  public @interface SchedulerSupport {
      /**
       * A special value indicating the operator/class doesn't use schedulers.
       */
      String NONE = "none";
      /**
       * A special value indicating the operator/class requires a scheduler to be manually specified.
       */
      String CUSTOM = "custom";
  
      // Built-in schedulers:
      /**
       * The operator/class runs on RxJava's {@linkplain Schedulers#computation() computation
       * scheduler} or takes timing information from it.
       */
      String COMPUTATION = "io.reactivex:computation";
      /**
       * The operator/class runs on RxJava's {@linkplain Schedulers#io() I/O scheduler} or takes
       * timing information from it.
       */
      String IO = "io.reactivex:io";
      /**
       * The operator/class runs on RxJava's {@linkplain Schedulers#newThread() new thread scheduler}
       * or takes timing information from it.
       */
      String NEW_THREAD = "io.reactivex:new-thread";
      /**
       * The operator/class runs on RxJava's {@linkplain Schedulers#trampoline() trampoline scheduler}
       * or takes timing information from it.
       */
      String TRAMPOLINE = "io.reactivex:trampoline";
      /**
       * The operator/class runs on RxJava's {@linkplain Schedulers#single() single scheduler}
       * or takes timing information from it.
       * <p>History: 2.0.8 - experimental
       * @since 2.2
       */
      String SINGLE = "io.reactivex:single";
  
      /**
       * The kind of scheduler the class or method uses.
       * @return the name of the scheduler the class or method uses
       */
      String value();
  }
  