Append error when more events that match the append query than the caller expects.
This implies that there is more information currently in the store that needs to be fetched in order for the decision model to determine whether the append is still valid.
Summary
Types
@type t() :: %Sourced.EventStore.OptimisticConcurrencyError{ __exception__: term(), actual: non_neg_integer(), expected: non_neg_integer() }