Struct Extensions 

pub struct Extensions { /* private fields */ }

A per-delivery type-map: at most one value per type, scoped to a single delivery.

Unlike the app-level State (shared, set once at build), an Extensions map is created fresh for each delivery and dropped when the handler returns, so one delivery’s values never leak into the next. A broker contributes typed per-delivery data through IncomingMessage::extensions (native delivery metadata, a commit token, a reply-to handle) without going through the byte-only headers; middleware may write entries for downstream handlers (via Context::insert); and the values are reachable from the publish path so a transactional publisher can read a broker-supplied commit token at commit time.

Examples

use ruststream::Extensions;

let mut ext = Extensions::new();
ext.insert(7u32);
assert_eq!(*ext.get::<u32>()?, 7);

Implementations

impl Extensions

pub fn new() -> Self

Creates an empty map.

Examples

use ruststream::Extensions;

let ext = Extensions::new();
assert!(ext.is_empty());

pub fn insert<T: Any + Send + Sync>(&mut self, value: T)

Inserts value, replacing any previous value of the same type.

Examples

use ruststream::Extensions;

let mut ext = Extensions::new();
ext.insert("first");
ext.insert("second");
assert_eq!(*ext.get::<&str>()?, "second");

pub fn get<T: Any + Send + Sync>(&self) -> Option<&T>

Returns the stored value of type T, if any.

Examples

use ruststream::Extensions;

let mut ext = Extensions::new();
ext.insert(42u64);
assert_eq!(ext.get::<u64>(), Some(&42));
assert_eq!(ext.get::<i8>(), None);

pub fn is_empty(&self) -> bool

Whether the map holds no entries.

Examples

use ruststream::Extensions;

let mut ext = Extensions::new();
assert!(ext.is_empty());
ext.insert(1u8);
assert!(!ext.is_empty());

Trait Implementations

impl Debug for Extensions

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Extensions

fn default() -> Extensions

Returns the “default value” for a type.