text: /*
   * Copyright 2016 Facebook, Inc.
   *
   * 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.
   */
  #include <folly/futures/Future.h>
  #include <folly/futures/ThreadWheelTimekeeper.h>
  #include <folly/Likely.h>
  
  namespace folly {
  
  // Instantiate the most common Future types to save compile time
  template class Future<Unit>;
  template class Future<bool>;
  template class Future<int>;
  template class Future<int64_t>;
  template class Future<std::string>;
  template class Future<double>;
  
  }
  
  namespace folly { namespace futures {
  
  Future<Unit> sleep(Duration dur, Timekeeper* tk) {
    std::shared_ptr<Timekeeper> tks;
    if (LIKELY(!tk)) {
      tks = folly::detail::getTimekeeperSingleton();
      tk = DCHECK_NOTNULL(tks.get());
    }
    return tk->after(dur);
  }
  
  }}
  