code: function (mutation) {
          // bail out for empty or unsupported mutations
          if (!(mutation && isPrimitiveMutation(mutation))) {
              return;
          }
  
          // if autoCompact is set, we need to compact while adding
          if (this.autoCompact) {
              this.addAndCompact(mutation);
              return;
          }
  
          // otherwise just push to the stream of mutations
          this.stream.push(mutation);
      }
docs: Records a new mutation.
  
  @private
  @param {MutationTracker~mutation} mutation