///|
fn main {
  // A resumable download: the client replays the Range header with the
  // validator it received earlier. When the validator no longer matches,
  // the conditional planner returns Ignore (status 200, full body).
  let request = @range.parse_range("bytes=1000-1999").unwrap()
  for
    validator in [
      "\"abc123\"", "\"stale-tag\"", "Sun, 06 Nov 1994 08:49:37 GMT",
    ] {
    match @range.parse_if_range(validator) {
      Err(error) => println("\{validator} -> \{error.to_string()}")
      Ok(if_range) => {
        let plan = @range.plan_conditional_range_response(
          request,
          5_000L,
          Some(if_range),
          "\"abc123\"",
          784_111_777L,
          true,
          true,
          true,
        ).unwrap()
        println("\{validator} -> status \{plan.recommended_status()}")
      }
    }
  }
}