@Override
  public JsonWriter value(String value) throws IOException {
    if (value == null) {
      generator.writeNull();
    } else {
      generator.writeString(value);
    }
    return this;
  }
{@link JsonWriter} implementation backed by Jackson's {@link JsonGenerator}.
Provides measurable JSON writing improvements over Gson's native implementation.
Error reporting is might differ, however.
gson/src/org/immutables/gson/stream/JsonGeneratorWriter.java