pub struct Lazy<T> { /* private fields */ }
Expand description

Lazy<T> is a lazily initialized synchronized holder type. You can think of it as a LazyTransform where the initial type doesn’t exist.

Implementations

Construct a new, uninitialized Lazy<T>.

Unwrap the contained value, returning Some if the Lazy<T> has been initialized or None if it has not.

Get a reference to the contained value, invoking f to create it if the Lazy<T> is uninitialized. It is guaranteed that if multiple calls to get_or_create race, only one will invoke its closure, and every call will receive a reference to the newly created value.

The value stored in the Lazy<T> is immutable after the closure returns it, so think carefully about what you want to put inside!

Get a reference to the contained value, returning Some(ref) if the Lazy<T> has been initialized or None if it has not. It is guaranteed that if a reference is returned it is to the value inside the Lazy<T>.

Trait Implementations

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Returns the “default value” for a type. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Convert Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>. Box<dyn Any> can then be further downcast into Box<ConcreteType> where ConcreteType implements Trait. Read more

Convert Rc<Trait> (where Trait: Downcast) to Rc<Any>. Rc<Any> can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait. Read more

Convert &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s. Read more

Convert &mut Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &mut Any’s vtable from &mut Trait’s. Read more

Convert Arc<Trait> (where Trait: Downcast) to Arc<Any>. Arc<Any> can then be further downcast into Arc<ConcreteType> where ConcreteType implements Trait. Read more

Use this to cast from one trait object type to another. Read more

Use this to upcast a trait to one of its supertraits. Read more

Use this to cast from one trait object type to another. This method is more customizable than the dyn_cast method. Here you can also specify the “source” trait from which the cast is defined. This can for example allow using casts from a supertrait of the current trait object. Read more

Use this to cast from one trait object type to another. With this method the type parameter is a config type that uniquely specifies which cast should be preformed. Read more

Returns the argument unchanged.

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more

Instruments this type with the current Span, returning an Instrumented wrapper. Read more

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

Should always be Self

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

Uses borrowed data to replace owned data, usually by cloning. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more