SharePoint and deployment of global.asax code

static readonly Log instance = new Log();

SPFarm farm = SPFarm.Local;
Guid traceGuid = farm.TraceSessionGuid;
unit result = NativeMethods.RegisterTraceGuids(ControlCallback, null, ref traceGuid, 0, IntPrt.Zero, null, null, out hTraceReg);
System.Diagnostics.Debug.Assert(result==NativeMethods.ERROR_SUCCESS, "TraceRegister result = " + result.ToString());