Uri configuration for call operation (#448)

* call options with ability to change from_uri & from_display_name

* call options with ability to change from_uri & from_display_name

---------

Co-authored-by: Volsavr <[email protected]>

Author: Volsavr

lib/sip_ua.dart

@@ -2,3 +2,6 @@ export 'src/enum_helper.dart';
 export 'src/sip_message.dart';
 export 'src/sip_ua_helper.dart';
 export 'src/transport_type.dart';
+export 'src/uri.dart';
+
+

lib/src/rtc_session.dart

@@ -307,6 +307,16 @@ class RTCSession extends EventManager implements Owner {
     _ua.contact!.outbound = true;
     _contact = _ua.contact.toString();
 
+    bool isFromUriOptionPresent = options['from_uri'] != null;
+
+    //set from_uri and from_display_name if present
+    if (isFromUriOptionPresent) {
+      requestParams['from_display_name'] = options['from_display_name'] ?? '';
+      requestParams['from_uri'] = URI.parse(options['from_uri']);
+      extraHeaders
+        .add('P-Preferred-Identity: ${_ua.configuration.uri.toString()}');
+    }
+
     if (anonymous) {
       requestParams['from_display_name'] = 'Anonymous';
       requestParams['from_uri'] = URI('sip', 'anonymous', 'anonymous.invalid');