text: #ifndef _RIO_H
  #define _RIO_H
  #include <unistd.h>
  
  #define MAXLINE 1024 /* max length of a line */
  #define WEB_RIO_BUFSIZE 1024
  
  typedef struct {
      int rio_fd;                    /* descriptor for this buf */
      int rio_cnt;                   /* unread byte in this buf */
      char *rio_bufptr;              /* next unread byte in this buf */
      char rio_buf[WEB_RIO_BUFSIZE]; /* internal buffer */
  } web_rio_t;
  
  ssize_t writen(int, void *, size_t);
  void rio_read_init(web_rio_t *, int);
  ssize_t rio_read_line(web_rio_t *, void *, size_t);
  #endif
  