error: `select!` can't be empty
 --> $DIR/complete_only.rs:3:9
  |
3 | /         allochronic_util::select![
4 | |             complete => return,
5 | |         ]
  | |_________^
  |
  = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)