fn decode_chunk_8(
    input: &[u8],
    index_at_start_of_input: usize,
    decode_table: &[u8; 256],
    output: &mut [u8],
) -> Result<(), DecodeError>Expand description
Decode 8 bytes of input into 6 bytes of output.
input is the 8 bytes to decode.
index_at_start_of_input is the offset in the overall input (used for reporting errors
accurately)
decode_table is the lookup table for the particular base64 alphabet.
output will have its first 6 bytes overwritten