@type t() :: %Hemdal.Event{
  alert: Hemdal.Config.Alert.t() | nil,
  fail_duration: non_neg_integer(),
  fail_started: NaiveDateTime.t() | nil,
  last_update: NaiveDateTime.t(),
  metadata: map(),
  prev_status: Hemdal.Check.status(),
  status: Hemdal.Check.status()
}

The event is generated usually in Hemdal.Check module and it's based on the structure:

• alert based on Hemdal.Config.Alert
• status which is the current status to notify
• prev_status which is the previous status
• fail_started when the fail started to happens
• fail_duration how long the fail is/was
• last_update when the event was created
• metadata more information for the event