Function encode_writer 

pub fn encode_writer<W>(
    writer: &mut W,
    pixels: &DecodedPixels,
    options: EncodeOptions,
) -> Result<(), ImageIoError>
where
    W: Write + Seek,

Encodes typed pixels to a seekable writer.

The codec backend receives a temporary owned CPU buffer. No device transfer occurs, and the source image remains unchanged.