add concurrenc future example

Concurrence_examples/concurrence_future_example.py

@@ -0,0 +1,23 @@
+import random
+import logging
+import concurrent.futures
+
+WORKER_COUNT = 10
+JOB_COUNT = 10
+
+class Job:
+    def __init__(self, number):
+        self.number = number
+
+def process_job(job):
+    # Wait between 0 and 0.01 seconds.
+    time.sleep(random.random()/100.0)
+    logging.info("Job number {:d}".format(job.number))
+    
+def main():
+    with concurrent.futures.ThreadPoolExecutor(
+         max_workers=WORKER_COUNT) as executor:
+       futures = [executor.submit(process_job, Job(i))
+                        for i in range(JOB_COUNT)]
+       for future in concurrent.futures.as_completed(futures):
+           pass