function realDone(error, outputTree, file) {
        const resultingTree =
          /** @type {TailTree extends undefined ? Node : TailTree} */ (
            outputTree || tree
          )

        if (error) {
          reject(error)
        } else if (resolve) {
          resolve(resultingTree)
        } else {
          assert(done, '`done` is defined if `resolve` is not')
          done(undefined, resultingTree, file)
        }
      }
@param {Error | undefined} error
@param {Node} outputTree
@param {VFile} file
@returns {undefined}