public static PersistentEvent ToSessionStartEvent(this PersistentEvent source, DateTime? lastActivityUtc = null, bool? isSessionEnd = null, bool hasPremiumFeatures = true) {
            var startEvent = new PersistentEvent {
                SessionId = source.SessionId,
                Date = source.Date,
                Geo = source.Geo,
                OrganizationId = source.OrganizationId,
                ProjectId = source.ProjectId,
                Type = Event.KnownTypes.Session,
                Value = 0
            };

            var ei = source.GetEnvironmentInfo();
            if (ei != null) {
                startEvent.SetEnvironmentInfo(new EnvironmentInfo {
                    Architecture = ei.Architecture,
                    CommandLine = ei.CommandLine,
                    Data = ei.Data,
                    InstallId = ei.InstallId,
                    IpAddress = ei.IpAddress,
                    MachineName = ei.MachineName,
                    OSName = ei.OSName,
                    OSVersion = ei.OSVersion,
                    ProcessId = ei.ProcessId,
                    ProcessName = ei.ProcessName,
                    ProcessorCount = ei.ProcessorCount,
                    RuntimeVersion = ei.RuntimeVersion,
                    TotalPhysicalMemory = ei.TotalPhysicalMemory
                });
            }

            var ri = source.GetRequestInfo();
            if (ri != null) {
                startEvent.AddRequestInfo(new RequestInfo {
                    ClientIpAddress = ri.ClientIpAddress,
                    Data = ri.Data,
                    Host = ri.Host,
                    HttpMethod = ri.HttpMethod,
                    IsSecure = ri.IsSecure,
                    Port = ri.Port,
                    Path = ri.Path,
                    Referrer = ri.Referrer,
                    UserAgent = ri.UserAgent
                });
            }
            
            startEvent.SetVersion(source.GetVersion());
            startEvent.SetUserIdentity(source.GetUserIdentity());

            if (lastActivityUtc.HasValue)
                startEvent.UpdateSessionStart(lastActivityUtc.Value, isSessionEnd.GetValueOrDefault());

            if (hasPremiumFeatures)
                startEvent.CopyDataToIndex();
            
            return startEvent;
        }