A bitset with a const generic size parameter indicating the number of 64 bit words to use. Can be used in no-std as it does not allocate.
use const_sized_bit_set::*;
// This set has 2 64-bit words so this set can contain values in 0..=127
let mut set = BitSet::<2>::from_iter([0,1, 99].into_iter());
set.remove(1);
set.insert(100);
assert_eq!(set.to_string(), "[0, 99, 100]");