private ReflectiveTypeAdapterFactory.BoundField createBoundField(
      final Gson context, final Field field, final String name,
      final TypeToken<?> fieldType, boolean serialize, boolean deserialize) {
    final boolean isPrimitive = Primitives.isPrimitive(fieldType.getRawType());
    // special casing primitives here saves ~5% on Android...
    return new ReflectiveTypeAdapterFactory.BoundField(name, serialize, deserialize) {
      final TypeAdapter<?> typeAdapter = getFieldAdapter(context, field, fieldType);
      @SuppressWarnings({"unchecked", "rawtypes"}) // the type adapter and field type always agree
      @Override void write(JsonWriter writer, Object value)
          throws IOException, IllegalAccessException {
        Object fieldValue = field.get(value);
        TypeAdapter t =
          new TypeAdapterRuntimeTypeWrapper(context, this.typeAdapter, fieldType.getType());
        t.write(writer, fieldValue);
      }
      @Override void read(JsonReader reader, Object value)
          throws IOException, IllegalAccessException {
        Object fieldValue = typeAdapter.read(reader);
        if (fieldValue != null || !isPrimitive) {
          field.set(value, fieldValue);
        }
      }
    };
  }