Function second_last_continuation_byte Copy item path

has_width_3_encoding(scalar) || has_width_4_encoding(scalar),

{ 0x80 | ((scalar >> 6) & 0x3F) as u8 }

The second-to-last continuation byte of the UTF-8 encoding of the given scalar value, assuming that the scalar has a 3 or 4-byte UTF-8 encoding.