@type effect() ::
  :drop_responses
  | {:wkc_offset, integer()}
  | {:command_wkc_offset, atom(), integer()}
  | {:logical_wkc_offset, atom(), integer()}
  | {:disconnect, atom()}
  | {:retreat_to_safeop, atom()}
  | {:power_cycle, atom()}
  | {:latch_al_error, atom(), non_neg_integer()}
  | {:mailbox_abort, atom(), non_neg_integer(), non_neg_integer(),
     non_neg_integer(), mailbox_step() | nil}
  | {:mailbox_protocol_fault, atom(), non_neg_integer(), non_neg_integer(),
     mailbox_step(), term()}
  | {:nested, t() | raw_fault()}
  | {:script, [t()]}
  | {:wait_for_milestone, milestone()}

@type mailbox_step() ::
  :request | :upload_init | :upload_segment | :download_init | :download_segment

@type milestone() ::
  {:healthy_exchanges, pos_integer()}
  | {:healthy_polls, atom(), pos_integer()}
  | {:mailbox_step, atom(), mailbox_step(), pos_integer()}

@type raw_fault() ::
  EtherCAT.Simulator.fault()
  | EtherCAT.Simulator.immediate_fault()
  | EtherCAT.Simulator.fault_script_step()

@type schedule() ::
  :immediate
  | {:next_exchange, pos_integer()}
  | {:after_ms, non_neg_integer()}
  | {:after_milestone, milestone()}

@type t() :: %EtherCAT.Simulator.Fault{effect: effect(), schedule: schedule()}