System.Data.SqlClient.TdsParser.EnableMars C# (CSharp) Method

        internal void EnableMars()
        {
            if (_fMARS)
            {
                // Cache physical stateObj and connection.
                _pMarsPhysicalConObj = _physicalStateObj;

                uint error = 0;

#if MANAGED_SNI
                _pMarsPhysicalConObj.IncrementPendingCallbacks();
                error = SNIProxy.Singleton.EnableMars(_pMarsPhysicalConObj.Handle);
#else
                // Add SMUX (MARS) SNI provider.
                UInt32 info = 0;
                error = SNINativeMethodWrapper.SNIAddProvider(_pMarsPhysicalConObj.Handle, SNINativeMethodWrapper.ProviderEnum.SMUX_PROV, ref info);
#endif // MANAGED_SNI

                if (error != TdsEnums.SNI_SUCCESS)
                {
                    _physicalStateObj.AddError(ProcessSNIError(_physicalStateObj));
                    ThrowExceptionAndWarning(_physicalStateObj);
                }

#if !MANAGED_SNI
                // HACK HACK HACK - for Async only
                // Have to post read to initialize MARS - will get callback on this when connection goes
                // down or is closed.

                IntPtr temp = IntPtr.Zero;

                try { }
                finally
                {
                    _pMarsPhysicalConObj.IncrementPendingCallbacks();

                    error = SNINativeMethodWrapper.SNIReadAsync(_pMarsPhysicalConObj.Handle, ref temp);

                    if (temp != IntPtr.Zero)
                    {
                        // Be sure to release packet, otherwise it will be leaked by native.
                        SNINativeMethodWrapper.SNIPacketRelease(temp);
                    }
                }
                Debug.Assert(IntPtr.Zero == temp, "unexpected syncReadPacket without corresponding SNIPacketRelease");
                if (TdsEnums.SNI_SUCCESS_IO_PENDING != error)
                {
                    Debug.Assert(TdsEnums.SNI_SUCCESS != error, "Unexpected successful read async on physical connection before enabling MARS!");
                    _physicalStateObj.AddError(ProcessSNIError(_physicalStateObj));
                    ThrowExceptionAndWarning(_physicalStateObj);
                }
#endif // MANAGED_SNI

                _physicalStateObj = CreateSession(); // Create and open default MARS stateObj and connection.
            }
        }