containsKey method

@override Future<bool> containsKey(String key)

Determines if the Cache contains an entry for the specified key.

• key: key whose presence in this cache is to be tested.

Returns true if this Cache contains a mapping for the specified key and the value is not expired

Implementation

@override
Future<bool> containsKey(String key) =>
    _primary.containsKey(key).then((contains) =>
        contains ? Future.value(true) : _secondary.containsKey(key));