Expose a way to identify the number of detected bodies

[grrrwaaa]

According to the MSDN docs:

"The BodyIndexFrame Class represents a frame that is computed based on the depth image. This image tells you which depth or infrared pixels belong to tracked people and which belong to the background. The pixel values in this frame are 8-bit unsigned integers, where 0-5 map directly to the BodyData index in the BodyFrame Class. Values greater than the value obtained from BodyFrameSource.BodyCount Property indicate that the pixel is part of the background, not associated with a tracked body. This frame is useful for green screening applications..."
https://msdn.microsoft.com/en-us/library/dn782033.aspx

There doesn't seem to be a way to access this BodyFrameSource.BodyCount from the KCB2 API. BodyFrame::getBodies().size() always returns 6, for example, regardless whether any bodies are visible. Is there another way?