Replace RacyFlag with OnceCell

crates/stdx/src/lib.rs

@@ -1,8 +1,5 @@
 //! Missing batteries for standard libraries.
-use std::{
-    sync::atomic::{AtomicUsize, Ordering},
-    time::Instant,
-};
+use std::time::Instant;
 
 mod macros;
 pub mod panic_context;
@@ -150,31 +147,6 @@ where
     left
 }
 
-pub struct RacyFlag(AtomicUsize);
-
-impl RacyFlag {
-    pub const fn new() -> RacyFlag {
-        RacyFlag(AtomicUsize::new(!0))
-    }
-
-    pub fn get(&self, init: impl FnMut() -> bool) -> bool {
-        let mut init = Some(init);
-        self.get_impl(&mut || init.take().map_or(false, |mut f| f()))
-    }
-
-    fn get_impl(&self, init: &mut dyn FnMut() -> bool) -> bool {
-        match self.0.load(Ordering::Relaxed) {
-            0 => false,
-            1 => true,
-            _ => {
-                let res = init();
-                self.0.store(if res { 1 } else { 0 }, Ordering::Relaxed);
-                res
-            }
-        }
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;