// for encoding. It is _much_ slower than the reference implementation, but we
// encode only during build, and most time in build is spent in other things
// than encoding posting lists, so it only costs ~5-10% overall. Does not use
// for encoding. It is _much_ slower than the reference implementation, but we
// encode only during build, and most time in build is spent in other things
// than encoding posting lists, so it only costs ~5-10% overall. Does not use