Caps.getFeatures

Finds the features in caps at index, and returns it.

WARNING: This function takes a const GstCaps *, but returns a non-const GstCapsFeatures *. This is for programming convenience -- the caller should be aware that features inside a constant #GstCaps should not be modified. However, if you know the caps are writable, either because you have just copied them or made them writable with gst_caps_make_writable(), you may modify the features returned in the usual way, e.g. with functions like [gst.caps_features.CapsFeatures.add].