A FIFO that keeps all the values introduced at least for a given time. Applied to some device servers, to force States to be kept at least a minimum time. Previously named as PyTango_utils.device.StateQueue pop(): The value is removed only if delete_time has been reached. at least 1 value is always kept in the list
Inserts a tuple with (value,insert_time,delete_time=now+keep)
Returns the indicated value, or the first one; but removes only if delete_time has been reached. All values are returned at least once. When the queue has only a value, it is not deleted.