SIPSorcery.SIP.App.SIPClientUserAgent.GetUpdateRequest C# (CSharp) Method

        private SIPRequest GetUpdateRequest(SIPRequest inviteRequest, CRMHeaders crmHeaders)
        {
            SIPRequest updateRequest = new SIPRequest(SIPMethodsEnum.UPDATE, inviteRequest.URI);
            updateRequest.LocalSIPEndPoint = inviteRequest.LocalSIPEndPoint;

            SIPHeader inviteHeader = inviteRequest.Header;
            SIPHeader updateHeader = new SIPHeader(inviteHeader.From, inviteHeader.To, inviteHeader.CSeq + 1, inviteHeader.CallId);
            inviteRequest.Header.CSeq++;
            updateRequest.Header = updateHeader;
            updateHeader.CSeqMethod = SIPMethodsEnum.UPDATE;
            updateHeader.Routes = inviteHeader.Routes;
            updateHeader.ProxySendFrom = inviteHeader.ProxySendFrom;

            SIPViaHeader viaHeader = new SIPViaHeader(inviteRequest.LocalSIPEndPoint, CallProperties.CreateBranchId());
            updateHeader.Vias.PushViaHeader(viaHeader);

            // Add custom CRM headers.
            if (crmHeaders != null)
            {
                updateHeader.CRMPersonName = crmHeaders.PersonName;
                updateHeader.CRMCompanyName = crmHeaders.CompanyName;
                updateHeader.CRMPictureURL = crmHeaders.AvatarURL;
            }

            return updateRequest;
        }