def subscribe(requestor, service, nodeIdentifier, subscriber):
Checks if the local file is identical to the S3 key by using the file's md5 hash.
dataset/ETHPy150Open ralphm/wokkel/wokkel/iwokkel.py/IPubSubService.subscribe--crossover with--dataset/ETHPy150Open quid/s3concurrent/s3concurrent/s3concurrent.py/is_sync_needed