code: public void writeValue (String name, Object value, Class knownType) {
  		try {
  			writer.name(name);
  		} catch (IOException ex) {
  			throw new JsonException(ex);
  		}
  		writeValue(value, knownType, null);
  	}
docs: Writes the value as a field on the current JSON object, writing the class of the object if it differs from the specified
  known type.
  @param value May be null.
  @param knownType May be null if the type is unknown.
  @see #writeValue(String, Object, Class, Class)