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pub struct VacantEntry<'a, VE: ValueEncoding> { /* private fields */ }
Expand description

A view into a single empty location in a MetadataMap.

This struct is returned as part of the Entry enum.

Implementations

Returns a reference to the entry’s key

Examples
let mut map = MetadataMap::new();

assert_eq!(map.entry("x-hello").unwrap().key(), "x-hello");

Take ownership of the key

Examples
let mut map = MetadataMap::new();

if let Entry::Vacant(v) = map.entry("x-hello").unwrap() {
    assert_eq!(v.into_key().as_str(), "x-hello");
}

Insert the value into the entry.

The value will be associated with this entry’s key. A mutable reference to the inserted value will be returned.

Examples
let mut map = MetadataMap::new();

if let Entry::Vacant(v) = map.entry("x-hello").unwrap() {
    v.insert("world".parse().unwrap());
}

assert_eq!(map.get("x-hello").unwrap(), "world");
source

pub fn insert_entry(self, value: MetadataValue<VE>) -> OccupiedEntry<'a, Ascii>

Insert the value into the entry.

The value will be associated with this entry’s key. The new OccupiedEntry is returned, allowing for further manipulation.

Examples
let mut map = MetadataMap::new();

if let Entry::Vacant(v) = map.entry("x-hello").unwrap() {
    let mut e = v.insert_entry("world".parse().unwrap());
    e.insert("world2".parse().unwrap());
}

assert_eq!(map.get("x-hello").unwrap(), "world2");

Trait Implementations

Formats the value using the given formatter. 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

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.

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