pub const INVALID_ENTRY_INDEX: usize = usize::MAX; // 18_446_744_073_709_551_615usizeExpand description
Sentinel value indicating an ActionServerRawHandle is not bound to an
arena entry yet. Used by Phase 87.5 to replace Option<...> with a
#[repr(C)]-compatible inline field.
Function pointers are populated with unreachable_* stubs that panic
if anyone is reckless enough to dispatch through an unbound handle —
callers must check entry_index == INVALID_ENTRY_INDEX first.