anchor.diff:  +s_mach.concurrent+ is an open-source Scala library that provides concurrent execution flow control primitives for
   working with the scala.concurrent standard library.
   
  -* Adds new flow control primitives +concurrently+, +serially+ and +workers+ for control of concurrent collection operations
  +* Adds new flow control primitives +concurrently+, +serially+ and +workers+ for control of collection concurrent operations
  +* Adds retry and throttle control for collection concurrent operations
   * Adds +ScheduledExecutionContext+, a wrapper for +java.util.concurrent.ScheduledExecutorService+ that provides a functional style interface for scheduling delayed and periodic tasks
   * Adds common concurrent control mechanisms such as concurrent versions of +Latch+, +Lock+, +Semaphore+ and +Queue+
   * Overcomes some design limitations of the scala.concurrent library
  
positive.code: 
  The same code, rewritten using +s_mach.concurrent+:
  
  .Example 5: Using +s_mach.concurrent+ to serially or concurrently transform and traverse collections:
  [source,scala,numbered]
  ----
  val oomItemIdBatch = (1 to 10).toList.map(_.toString).grouped(2).toList
  
negative.code: +flatMerge+ methods fixes these problems by throwing +ConcurrentThrowable+. +ConcurrentThrowable+ has a member method to
  access both the first exception thrown and a future of all exceptions thrown during the computation.
  
  .Example 6: +Future.sequence+ gets stuck waiting on longRead to complete and only returns the first exception:
  [source,scala,numbered]
  ----
  scala> val t = Future.sequence(Vector(longRead("1"),readFail("2"),readFail("3"),read("4"))).getTry
  