message: lifetime independence of groups
diff: @@ -406,7 +406,7 @@ impl<'a> Group<'a> {
  }
  }
  - pub fn open_group(&self, name: &str, options: CslStringList) -> Result<Group> {
  + pub fn open_group(&'_ self, name: &str, options: CslStringList) -> Result<Group<'a>> {
  let name = CString::new(name)?;
  unsafe {
  @@ -945,6 +945,9 @@ mod tests {
  let group_grids = group_science
  .open_group("grids", CslStringList::new())
  .unwrap();
  +
  + drop(group_science); // check that `Group`s do not borrow each other
  +
  let group_data = group_grids
  .open_group("data", CslStringList::new())
  .unwrap();
  