Function libwebp::WebPEncodeLosslessBGRA

pub fn WebPEncodeLosslessBGRA(
    bgra: &[u8], 
    width: u32, 
    height: u32, 
    stride: u32
) -> Result<WebpBox<[u8]>, WebPSimpleError>

Same as WebPEncodeLosslessRGBA, but expecting B, G, R, A, B, G, R, A... ordered data.