using Datagrammer.Sip;
using Sip.Protocol;

var sipMessageBytes = new SipBuilderStep().SetRequestHeader("REGISTER", "sip:ss2.wcom.com")
                                          .AddHeader("Via", "SIP/2.0/UDP there.com:5060;branch=wsodil7987kjh")
                                          .AddHeader("From", "SomeGuy <sip:User@there.com>")
                                          .AddHeader("Content-Length", "3")
                                          .SetBody(new byte[] { 1, 2, 3 })
                                          .Build();