Need help with getting latest 5 mins of real time data in C# SDK

Hello folks,
I am a C# guy, and I really like to stick with SDK instead of row HTTP request that I need to create my own data model. I want to get the latest 5 mins bar data. The GetHistoricalBarsAsync(hist) works really well, however, it only shows delay data from the last 15 mins.
GetLatestBarAsync() works ok, and I am suprised that it does not allow me to pass the timeframe data, so it always only return bar in 1 mins interval. I could aggregate the 1 min bars into a 5 min bar, but just wondering if there is an easier way to get latest 5 mins of data. thanks!