anchor.diff:  tuple value results can be extracted using normal Scala idioms. The +concurrently+ method also fixes problems with
   +scala.concurrent+ exception handling (see the 'Under the hood: Merge' section below).
   
  -=== Under the hood: +Merge+ method
  +== Under the hood: +Merge+ method
   Powering both the tuple +concurrently+ method and the collection +.concurrently.map+, +.concurrently.flatMap+ and
   +.concurrently.foreach+ methods is the +merge+ and +flatMerge+ methods. The +merge+ method performs the same
   function as +Future.sequence+ (it calls +Future.sequence+ internally) but it ensures that the returned future completes
  
positive.code:       println("Writing...")
        oomNewItemBatch.serially.flatMap(_.concurrently.map(item => write(item.id, item)))
      }
    } yield oomResult.forall(_ === true)
  }
  ----
  
  === Transforming and traversing collections using workers
  
  +s_mach.concurrent+ provides the +workers+ method which allows specifying the maximum number of concurrent operations.
  
  
negative.code:           } yield acc ::: oomResult
          }
      }
    } yield oomResult.forall(_ == true)
  }
  ----
  
  