           vEncoding ?= 'utf8'
           @encoding = vEncoding
         else
-          @encoding = null
+          @encoding = undefined
         @skipSize = aOptions.skipSize if @skipSize isnt aOptions.skipSize
         @_contents = result
     else

            vEncoding ?= 'utf8'
            @encoding = vEncoding
          else
            @encoding = null
          @_contents = @_loadContentSync(aOptions)
        else
          ### !pragma coverage-skip-next ###

                vEncoding ?= 'utf8'
                @encoding = vEncoding
              else
                @encoding = undefined
              @_contents = result
              @skipSize = aOptions.skipSize if @skipSize isnt aOptions.skipSize
            done.call @, err, result
