@type t() :: %HL7v2.Segment.FHS{
  extra_fields: term(),
  file_control_id: term(),
  file_creation_date_time: term(),
  file_encoding_characters: term(),
  file_field_separator: term(),
  file_header_comment: term(),
  file_name_id: term(),
  file_receiving_application: term(),
  file_receiving_facility: term(),
  file_security: term(),
  file_sending_application: term(),
  file_sending_facility: term(),
  reference_file_control_id: term()
}