public PlaceDetailsRequest fields(FieldMask... fields) {
    return param("fields", StringJoin.join(',', fields));
  }
Specifies the field masks of the details to be returned by PlaceDetails.

@param fields The Field Masks of the fields to return.
@return Returns this {@code PlaceDetailsRequest} for call chaining.
src/main/java/com/google/maps/PlaceDetailsRequest.java