remove typedef we ended up not using

                                      size_t nitems,

                                      void *outstream);

typedef size_t (*curl_rtp_write_callback)(char *buffer,

                                      size_t size,

                                      size_t nitems,

                                      void *outstream,

                                      int channel);

/* These are the return codes for the seek callbacks */

#define CURL_SEEKFUNC_OK       0

#define CURL_SEEKFUNC_FAIL     1 /* fail the entire transfer */