1. The REFER I get:
2.    REFER sip:44555202@172.16.16.141:9781;transport=udp SIP/2.0
3.    Via: SIP/2.0/UDP 172.16.16.130:5060;branch=z9hG4bK-524287-1---cca7663c48d77f3a;rport
4.    Via: SIP/2.0/UDP 192.168.63.72:5061;branch=z9hG4bK-2b6d69c5
5.    Max-Forwards: 69
6.    Contact: <sip:44111200@192.168.63.72:5061>
7.    To: <sip:44555202@172.16.16.130>;tag=a1r2KaQ5Q3vUm
8.    From: <sip:44111200@172.16.16.130>;tag=33099d38e40eb484o1
9.    Call-ID: b0184248-ae01d2b4@192.168.63.72
10.    CSeq: 103 REFER
11.    User-Agent: Cisco/SPA504G-7.6.0
12.    Refer-To: <sip:44555204@172.16.16.130?Replaces=e1d8e9ed-f4fa54d8%40192.168.63.72%3Bfrom-tag%3D7fbc6ee9cfb6340co1%3Bto-tag%3DBajUN578mcKeg>
13.    Referred-By: <sip:44111200@172.16.16.130>
14.    Content-Length: 0
15.  
16. The part of RFC 3515 saying a body is not mandatory:
17. 2.3 Message Body Inclusion
18.  
19.    A REFER method MAY contain a body.  This specification assigns no
20.    meaning to such a body.  A receiving agent may choose to process the
21.    body according to its Content-Type.
22.  
23.  
24.  
25. Original code not firing the event if the REFER does not have a body+content-type:
26.         if (sip->sip_content_type &&
27.                 sip->sip_content_type->c_type && sip->sip_payload && sip->sip_payload->pl_data && !strcasecmp(sip->sip_event->o_type, "refer")) {
28.                 if (switch_event_create_subclass(&s_event, SWITCH_EVENT_CUSTOM, MY_EVENT_NOTIFY_REFER) == SWITCH_STATUS_SUCCESS) {
29.                         switch_event_add_header_string(s_event, SWITCH_STACK_BOTTOM, "content-type", sip->sip_content_type->c_type);
30.                         switch_event_add_body(s_event, "%s", sip->sip_payload->pl_data);
31.                 }
32.         }
33.  
34.  
35. What I think the code should be like to cope with a REFER without a body (not tested yet):
36.   if (!strcasecmp(sip->sip_event->o_type, "refer")) {
37.     if (switch_event_create_subclass(&s_event, SWITCH_EVENT_CUSTOM, MY_EVENT_NOTIFY_REFER) == SWITCH_STATUS_SUCCESS) {
38.       if (sip->sip_content_type && sip->sip_content_type->c_type && sip->sip_payload && sip->sip_payload->pl_data) {
39.         switch_event_add_header_string(s_event, SWITCH_STACK_BOTTOM, "content-type", sip->sip_content_type->c_type);
40.         switch_event_add_body(s_event, "%s", sip->sip_payload->pl_data);
41.       }
42.     }
43.   }
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