pub fn read_bit_string(input: &[u8]) -> Option<(u8, &[u8], &[u8])>Expand description
Read a DER BIT STRING.
Returns (unused_bits, value_bytes, rest). unused_bits is the
count from the first content byte; for the SPKI uncompressed-
point case this MUST be 0 — caller checks. unused_bits > 7
is rejected. An empty BIT STRING value (no unused_bits byte
at all) is also rejected.