Inserting causes a pianic

[otisdog8]

Ran with one thread, haven't made efforts on reproducing but it appears to happen when my system is under heavy load. Also occurs when running with multiple threads.

thread 'main' panicked at /root/.cargo/registry/src/index.crates.io-6f17d22bba15001f/leapfrog-0.3.0/src/leapmap.rs:783:13:
assertion failed: migrator.stale_sources[index].load(Ordering::Relaxed).is_null()
stack backtrace:
   0: rust_begin_unwind
             at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/panicking.rs:645:5
   1: core::panicking::panic_fmt
             at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/core/src/panicking.rs:72:14
   2: core::panicking::panic
             at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/core/src/panicking.rs:144:5
   3: leapfrog::leapmap::LeapMap<K,V,H,A>::initialize_migrator
             at /root/.cargo/registry/src/index.crates.io-6f17d22bba15001f/leapfrog-0.3.0/src/leapmap.rs:783:13
   4: leapfrog::leapmap::LeapMap<K,V,H,A>::insert
             at /root/.cargo/registry/src/index.crates.io-6f17d22bba15001f/leapfrog-0.3.0/src/leapmap.rs:386:25