fn
fn b64_encode(s: string) -> string
Standard Base64 encode (RFC 4648, with = padding). Each group of three input bytes becomes four output characters; the last group is padded so the output is always a multiple of four.
b64_encode("Hello"); // "SGVsbG8="
b64_encode("foobar"); // "Zm9vYmFy"
b64_encode(""); // ""