Function encode_gray10 

pub fn encode_gray10(
    gray: &[u16],
    width: u32,
    height: u32,
    cfg: &EncodeConfig,
) -> Result<Vec<u8>, EncodeError>

Encode a 10-bit greyscale image to HEIC.

gray must hold exactly width * height samples in 0..=1023, packed as u16.