Type Alias OnceCell 

pub type OnceCell<T> = OnceCell<T>;

Available on crate feature once_cell only.

A thread-safe cell which can be written to only once.

Note: We use once_cell here because std::sync::OnceLock::get_or_try_init() is not yet stable. Once it’s stabilized, we can switch to std::sync::OnceLock.

Aliased Type

pub struct OnceCell<T>(/* private fields */);