Measure execution time with a closure

Measures the execution time with a closure.

def benchmark = { closure ->
  start = System.currentTimeMillis()
  closure.call()
  now = System.currentTimeMillis()
  now - start
}
def duration = benchmark {
	(0..10000).inject(0) { sum, item ->
		sum + item
	}
}
println "execution took ${duration} ms"