obs-outputs/librtmp: Add custom connect data callback

Allows the ability to add custom connect data to the connect signal
encoding

plugins/obs-outputs/librtmp/rtmp.c

@@ -1684,6 +1684,11 @@ SendConnectPacket(RTMP *r, RTMPPacket *cp)
         enc = AMF_EncodeNamedString(enc, pend, &av_type, &av_nonprivate);
         if (!enc)
             return FALSE;
+
+        if (r->Link.customConnectEncode)
+        {
+            r->Link.customConnectEncode(&enc, pend);
+        }
     }
     if (r->Link.flashVer.av_len)
     {

plugins/obs-outputs/librtmp/rtmp.h

@@ -285,6 +285,8 @@ extern "C"
         AVal playpath;
     } RTMP_Stream;
 
+    typedef void (*CUSTOMCONNECTENCODING)(char **penc, char *ppend);
+
     typedef struct RTMP_LNK
     {
 #define RTMP_MAX_STREAMS 8
@@ -296,6 +298,8 @@ extern "C"
         AVal hostname;
         AVal sockshost;
 
+        CUSTOMCONNECTENCODING customConnectEncode;
+
         AVal tcUrl;
         AVal swfUrl;
         AVal pageUrl;