function Transform(init, params) {
    Operator.call(this, init, null, params);
  }
Abstract class for operators that process data tuples.
Subclasses must provide a {@link transform} method for operator processing.
@constructor
@param {*} [init] - The initial value for this operator.
@param {object} [params] - The parameters for this operator.
@param {Operator} [source] - The operator from which to receive pulses.