pub fn remove_entry(self) -> (MetadataKey<VE>, MetadataValue<VE>) {
        let (name, value) = self.inner.remove_entry();
        (
            MetadataKey::unchecked_from_header_name(name),
            MetadataValue::unchecked_from_header_value(value),
        )
    }
Remove the entry from the map.

The key and all values associated with the entry are removed and the
first one is returned. See `remove_entry_mult` for an API that returns
all values.

# Examples

```
# use tonic::metadata::*;
let mut map = MetadataMap::new();
map.insert("host", "world".parse().unwrap());

if let Entry::Occupied(e) = map.entry("host").unwrap() {
let (key, mut prev) = e.remove_entry();
assert_eq!("host", key.as_str());
assert_eq!("world", prev);
}

assert!(!map.contains_key("host"));
```
tonic/src/metadata/map.rs