It is possible that we can't burst all of the data in the immediate data

It is possible that we can't burst all of the data in the immediate data
part of the write request. In that case R2T requests with be sent for the
rest of the data. The amount of data we can send is defined by
MaxRecvDataSegmentLength which is per connection and so a bit hackish to
read out. In the long run the min() of all connection MaxRecvDataSegmentLength
should be stored in the session struct.