ByAge tries to remove the messages at the start of the log before given time.

ByCount tries to remove messages to keep the number of messages in the log under max count.

ByOffset tries to remove the messages at the start of the log before offset returns the offsets it deleted and the amount of storage freed.

BySize tries to remove messages until log size is less then sz returns the offsets it deleted and the amount of storage freed.

FindByAge returns a set of offsets for messages that are at the start of the log and before given time.

FindByCount returns a set of offsets for messages that when removed will keep number of the messages in the log less then max.

FindByOffset returns a set of offsets for messages that offset is before a given offset.

FindBySize returns a set of offsets for messages that if deleted will decrease the log size to sz.