Function decode_to_slice 

pub fn decode_to_slice(src_hex: &[u8], dst: &mut [u8]) -> Result<usize, Error>

Decode ASCII-hex bytes src_hex into dst.

src_hex must contain an even number of bytes, all valid hex characters (0-9, a-f, A-F). dst must be at least src_hex.len() / 2 bytes.

Returns the number of bytes written.