@type t() :: %Spear.Filter.Checkpoint{
  commit_position: non_neg_integer(),
  prepare_position: non_neg_integer(),
  subscription: reference()
}

A struct representing a checkpoint in a server-side filter operation

When subscribing to the :all stream, one may provide a :filter option which the server will use to filter events before sending them over the network.

Since the results of a server-side filtering subscription can be sparsely spread out in the entire :all stream, the EventStoreDB emits checkpoints as it reads through the events.

A client can restore its position in a filter subscription by passing one of these structs to the :from option of Spear.subscribe/4.

See the Spear.Filter documentation for more information.