pub fn values(&self) -> Values<'_> {
        Values {
            inner: self.headers.iter(),
        }
    }
An iterator visiting all values (both ascii and binary).

The iteration order is arbitrary, but consistent across platforms for
the same crate version.

# Examples

```
# use tonic::metadata::*;
let mut map = MetadataMap::new();

map.insert("x-word", "hello".parse().unwrap());
map.append("x-word", "goodbye".parse().unwrap());
map.insert_bin("x-number-bin", MetadataValue::from_bytes(b"123"));

for value in map.values() {
match value {
ValueRef::Ascii(ref value) =>
println!("Ascii value: {:?}", value),
ValueRef::Binary(ref value) =>
println!("Binary value: {:?}", value),
}
println!("{:?}", value);
}
```
tonic/src/metadata/map.rs