pub struct Extensions { /* fields omitted */ }
A type map of protocol extensions.
Extensions
can be used by Request
and Response
to store
extra data derived from the underlying protocol.
Create an empty Extensions
.
Insert a type into this Extensions
.
If a extension of this type already existed, it will
be returned.
let mut ext = Extensions::new();
assert!(ext.insert(5i32).is_none());
assert!(ext.insert(4u8).is_none());
assert_eq!(ext.insert(9i32), Some(5i32));
Get a reference to a type previously inserted on this Extensions
.
let mut ext = Extensions::new();
assert!(ext.get::<i32>().is_none());
ext.insert(5i32);
assert_eq!(ext.get::<i32>(), Some(&5i32));
Get a mutable reference to a type previously inserted on this Extensions
.
let mut ext = Extensions::new();
ext.insert(String::from("Hello"));
ext.get_mut::<String>().unwrap().push_str(" World");
assert_eq!(ext.get::<String>().unwrap(), "Hello World");
Remove a type from this Extensions
.
If a extension of this type existed, it will be returned.
let mut ext = Extensions::new();
ext.insert(5i32);
assert_eq!(ext.remove::<i32>(), Some(5i32));
assert!(ext.get::<i32>().is_none());
Clear the Extensions
of all inserted extensions.
let mut ext = Extensions::new();
ext.insert(5i32);
ext.clear();
assert!(ext.get::<i32>().is_none());
Returns the "default value" for a type. Read more
Formats the value using the given formatter. Read more
🔬 This is a nightly-only experimental API. (try_from
)
The type returned in the event of a conversion error.
🔬 This is a nightly-only experimental API. (try_from
)
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more
🔬 This is a nightly-only experimental API. (try_from
)
The type returned in the event of a conversion error.
🔬 This is a nightly-only experimental API. (try_from
)
🔬 This is a nightly-only experimental API. (get_type_id
)
this method will likely be replaced by an associated static