text: //
  // Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2017
  //
  // Distributed under the Boost Software License, Version 1.0. (See accompanying
  // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  //
  #pragma once
  
  #include "td/telegram/td_api.h"
  
  #include "td/utils/common.h"
  #include "td/utils/StringBuilder.h"
  
  #include <functional>
  #include <type_traits>
  
  namespace td {
  class CallId {
   public:
    CallId() = default;
  
    explicit CallId(int32 call_id) : id(call_id) {
    }
  
    template <class T, typename = std::enable_if_t<std::is_convertible<T, int32>::value>>
    CallId(T call_id) = delete;
  
    bool is_valid() const {
      return id != 0;
    }
  
    int32 get() const {
      return id;
    }
  
    auto as_td_api() const {
      return make_tl_object<td_api::callId>(id);
    }
  
    bool operator==(const CallId &other) const {
      return id == other.id;
    }
  
   private:
    int32 id{0};
  };
  
  struct CallIdHash {
    std::size_t operator()(CallId call_id) const {
      return std::hash<int32>()(call_id.get());
    }
  };
  
  inline StringBuilder &operator<<(StringBuilder &sb, const CallId call_id) {
    return sb << "CallId(" << call_id.get() << ")";
  }
  }  // namespace td
  