public final E find(E key) {
        int index = findIndexOfEqualElement(key);
        if (index == INVALID_INDEX) {
            return null;
        }
        @SuppressWarnings("unchecked")
        E result = (E) elements[index];
        return result;
    }
An element e in the collection such that e.elementKeysAreEqual(key) and
e.hashCode() == key.hashCode().

@param key   The element to match.
@return      The matching element, or null if there were none.
clients/src/main/java/org/apache/kafka/common/utils/ImplicitLinkedHashCollection.java