subsetting samples

[brentp]

Hi, as far as I can tell, it's not possible (without using rust_htslib::htslib low level stuff) to subset bcf samples.
I see it happens in the tests, but those seem to be using private attributes.

I have put a full example here.
https://github.com/brentp/help-repositories/blob/rust-htslib-subset-samples/src/main.rs

Would someone help me to correctly open a file with many samples, subset to some samples, and write the output?
thanks,
-Brent