public V get(Object key) {
        final int index = indexOfKey(key);
        return index >= 0 ? (V)mArray[(index<<1)+1] : null;
    }
Retrieve a value from the array.
@param key The key of the value to retrieve.
@return Returns the value associated with the given key,
or null if there is no such key.
core/src/main/java/com/bluelinelabs/logansquare/util/SimpleArrayMap.java