src/protocol/evaluation.js
function Evaluation(evaluator, streamHandler) {
  _evaluationCounter++;
  this.counter = _evaluationCounter;

  this._evaluator = evaluator;
  this._streamHandler = streamHandler;
}
function Evaluation(evaluator, streamHandler) {
  _evaluationCounter++;
  this.counter = _evaluationCounter;

  this._evaluator = evaluator;
  this._streamHandler = streamHandler;
}
An Evaluation object that serves as context for a given code execution within the kernel. It sets up stdout/stderr capturing and restoring as well as async completion of the evaluation.