message: Add move constructor and explicit assignment operator to HTTPHeader
diff: @@ -1498,6 +1498,8 @@ public:
  type_ = HeaderType::ServerSet;
  }
  HTTPHeader( HTTPHeader const & ) = default;
  + HTTPHeader( HTTPHeader&& ) = default;
  + HTTPHeader& operator=( HTTPHeader const& ) = default;
  ~HTTPHeader() = default;
  public:
  