field_type() :: :single | :aggregate

t() :: %Csvto.Field{
  default: term(),
  field_index: integer() | nil,
  field_name: String.t() | nil,
  field_type: field_type(),
  file: String.t(),
  line: integer(),
  name: atom(),
  opts: Map.t(),
  required?: boolean(),
  type: atom(),
  validator: validator()
}

validator() :: {atom(), any()} | atom() | nil