Method is_readable

dependencies/httplib/httplib.h:4633–4635

inline SocketStream::~SocketStream() {}

inline bool SocketStream::is_readable() const {
  return select_read(sock_, read_timeout_sec_, read_timeout_usec_) > 0;
}

inline bool SocketStream::is_writable() const {
  return select_write(sock_, write_timeout_sec_, write_timeout_usec_) > 0;