Unable to compile in no_std project

I am trying to use `rclite` in a rp2040 project that is `no_std`. However, the library won't compile: ``` Compiling rclite v0.2.4 error[E0599]: no method named `fetch_sub` found for struct `AtomicUsize` in the current scope --> /Users/michael/.cargo/registry/src/index.crates.io-6f17d22bba15001f/rclite-0.2.4/src/arc.rs:434:26 | 434 | if inner.counter.fetch_sub(1, Ordering::Release) != 1 { | ^^^^^^^^^ method not found in `AtomicUsize` error[E0599]: no method named `fetch_add` found for struct `AtomicUsize` in the current scope --> /Users/michael/.cargo/registry/src/index.crates.io-6f17d22bba15001f/rclite-0.2.4/src/arc.rs:592:42 | 592 | let count = self.inner().counter.fetch_add(1, Ordering::Relaxed); | ^^^^^^^^^ method not found in `AtomicUsize` error[E0599]: no method named `fetch_sub` found for struct `AtomicUsize` in the current scope --> /Users/michael/.cargo/registry/src/index.crates.io-6f17d22bba15001f/rclite-0.2.4/src/arc.rs:609:33 | 609 | if self.inner().counter.fetch_sub(1, Ordering::Release) != 1 { | ^^^^^^^^^ method not found in `AtomicUsize` For more information about this error, try `rustc --explain E0599`. error: could not compile `rclite` (lib) due to 3 previous errors ``` I am using an extern allocator `embedded-alloc`. Any thoughts on what might be going wrong here?