private static TypeMirror getKeyType(TypeMirror type) {
    return MoreTypes.asDeclared(type).getTypeArguments().get(0);
  }
A {@link SerializerExtension} that deserializes objects inside an {@link ImmutableMap}.

<p>Enables unserializable objects inside an ImmutableMap to be serializable.
value/src/main/java/com/google/auto/value/extension/serializable/serializer/impl/ImmutableMapSerializerExtension.java