docs: function Cpu(kernel, number) {
      if (kernel === undefined || number === undefined)
        throw new Error('Missing arguments');
      this.kernel = kernel;
      this.cpuNumber = number;
      this.slices = [];
      this.counters = {};
      this.bounds = new tr.b.Range();
      this.samples_ = undefined; // Set during createSubSlices
  
      // Start timestamp of the last active thread.
      this.lastActiveTimestamp_ = undefined;
  
      // Identifier of the last active thread. On Linux, it's a pid while on
      // Windows it's a thread id.
      this.lastActiveThread_ = undefined;
  
      // Name and arguments of the last active thread.
      this.lastActiveName_ = undefined;
      this.lastActiveArgs_ = undefined;
    }