'Set fetch values based on blocking status'

def __enter__(self):

    self.orig_fetch_max_wait_time = self.consumer.fetch_max_wait_time
    self.orig_fetch_min_bytes = self.consumer.fetch_min_bytes
    if self.block:
        self.consumer.fetch_max_wait_time = self.timeout
        self.consumer.fetch_min_bytes = 1
    else:
        self.consumer.fetch_min_bytes = 0
