public String getType() {
      return property.getType();
    }
Writes the GWT serializer for the given type, if appropriate. An {@code @AutoValue} class gets
a GWT serializer if it is annotated with {@code @GwtCompatible(serializable = true)}, where the
{@code @GwtCompatible} annotation can come from any package.

<p>If the type is com.example.Foo then the generated AutoValue subclass is
com.example.AutoValue_Foo and the GWT serializer is
com.example.AutoValue_Foo_CustomFieldSerializer.

@param autoVars the template variables defined for this type.
@param finalSubclass the simple name of the AutoValue class being generated, AutoValue_Foo in
    the example.
value/src/main/java/com/google/auto/value/processor/GwtSerialization.java