Adding custom header

Custom headers can be specified when sending SIP requests, for example, when sending INVITE, IM message, etc. by specifying the headers in pjsua_msg_data structure, as shown in an example below:

pjsua_msg_data msg_data;
pjsip_generic_string_hdr my_hdr;
pj_str_t hname = pj_str("My-Header");
pj_str_t hvalue = pj_str("This is the content of My-Header");

pjsip_generic_string_hdr_init2(&my_hdr, &hname, &hvalue);
pj_list_push_back(&msg_data.hdr_list, &my_hdr);

// Specify the msg_data in pjsua_im_send(), for example
pjsua_im_send(.., &msg_data, NULL);