pub fn unescape_with<'input, 'entity, F>(
    raw: &'input str,
    resolve_entity: F,
) -> Result<Cow<'input, str>, EscapeError>Expand description
Unescape an &str and replaces all xml escaped characters (&...;) into
their corresponding value, using a resolver function for custom entities.
If feature escape-html is enabled, then recognizes all HTML5 escapes.
Predefined entities will be resolved after trying to resolve with resolve_entity,
which allows you to override default behavior which required in some XML dialects.
Character references (&#hh;) cannot be overridden, they are resolved before
calling resolve_entity.
Note, that entities will not be resolved recursively. In order to satisfy the XML requirements you should unescape nested entities by yourself.
ยงExample
use quick_xml::escape::resolve_xml_entity;
let override_named_entities = |entity: &str| match entity {
    // Override standard entities
    "lt" => Some("FOO"),
    "gt" => Some("BAR"),
    // Resolve custom entities
    "baz" => Some("<"),
    // Delegate other entities to the default implementation
    _ => resolve_xml_entity(entity),
};
assert_eq!(
    unescape_with("&<test>&baz;", override_named_entities).unwrap(),
    "&FOOtestBAR<"
);