//
// Every filesystem provides support for accessing URIs of form
// `[<scheme>://]<path>` where `<scheme>` is optional (if missing, we are
// accessing local paths). This test suite tests exactly one scheme for each
// invocation. By default, we are testing all schemes available but this can be
// restricted by using `--schemes` to specify a set of schemes to test.
//
// Example invocation:

  ///
  /// This is thread safe.
  ///
  /// Note: the `buffer` argument is NOT a null terminated string!
  ///
  /// Plugins:
  ///   * Must set `status` to `TF_OK` if exactly `n` bytes have been read.
  ///   * Must set `status` to `TF_OUT_OF_RANGE` if fewer than `n` bytes have
  ///     been read due to EOF.
  ///   * Must return -1 for any other error and must set `status` to any