class Concurrent::ReentrantReadWriteLock

def initialize

Create a new `ReentrantReadWriteLock` in the unlocked state. 
def initialize
  super()
  @Counter    = AtomicFixnum.new(0)       # single integer which represents lock state
  @ReadQueue  = Synchronization::Lock.new # used to queue waiting readers
  @WriteQueue = Synchronization::Lock.new # used to queue waiting writers
  @HeldCount  = LockLocalVar.new(0) # indicates # of R & W locks held by this thread
end