Function capacity

3rd/asio-1.24.0/include/asio/buffer.hpp:1811–1814

Get the maximum size that the buffer may grow to without triggering reallocation. * @returns The current capacity of the underlying string if less than * max_size(). Otherwise returns max_size(). */

   * max_size(). Otherwise returns max_size().
   */
  std::size_t capacity() const ASIO_NOEXCEPT
  {
    return (std::min)(string_.capacity(), max_size());
  }

#if !defined(ASIO_NO_DYNAMIC_BUFFER_V1)
  /// @b DynamicBuffer_v1: Get a list of buffers that represents the input