@type t() :: %ConfigCat.EvaluationDetails{
  default_value?: boolean(),
  error: String.t() | nil,
  fetch_time: DateTime.t() | nil,
  key: ConfigCat.Config.key(),
  matched_percentage_option: map() | nil,
  matched_targeting_rule: map() | nil,
  user: ConfigCat.User.t() | nil,
  value: ConfigCat.Config.value(),
  variation_id: ConfigCat.Config.variation_id() | nil
}

The results of evaluating a feature flag.

Fields:

• :default_value?: Indicates whether the default value passed to the setting evaluation functions like ConfigCat.get_value/3, ConfigCat.get_value_details/3, etc. is used as the result of the evaluation.
• :error: Error message in case evaluation failed.
• :fetch_time: Time of the last successful config download.
• :key: The key of the feature flag or setting.
• :matched_targeting_rule: The targeting rule (if any) that matched during the evaluation and was used to return the evaluated value.
• :matched_percentage_option: The percentage option (if any) that was used to select the evaluated value.
• :user: The ConfigCat.User struct used for the evaluation (if available).
• :value: Evaluated value of the feature flag or setting.
• :variation_id: Variation ID of the feature flag or setting (if available).