while (peekingItr.hasNext()) {
        Range<C> range = peekingItr.next();
        while (peekingItr.hasNext()) {
          Range<C> nextRange = peekingItr.peek();
          if (range.isConnected(nextRange)) {
            checkArgument(
                range.intersection(nextRange).isEmpty(),
                "Overlapping ranges not permitted but found %s overlapping %s",

    Deque<NodeAndRemainingSuccessors<N>> stack = new ArrayDeque<>();
    stack.addLast(new NodeAndRemainingSuccessors<>(startNode));

    while (!stack.isEmpty()) {
      // To peek at the top two items, we need to temporarily remove one.
      NodeAndRemainingSuccessors<N> top = stack.removeLast();
      NodeAndRemainingSuccessors<N> prev = stack.peekLast();
      stack.addLast(top);

    monitor.enterWhen(notEmpty);
    try {
      return extract();
    } finally {
      monitor.leave();
    }
  }

  @CanIgnoreReturnValue
  @Override
  public @Nullable E peek() {
    Monitor monitor = this.monitor;
    if (monitor.enterIf(notEmpty)) {
      try {
        return items[takeIndex];
      } finally {
        monitor.leave();
      }
    } else {

                    } catch (ExecutionException expected) {
                    }
                    try {
                      peeker.getDone(nonInput);
                      fail("Peeker should not be able to peek into non-input ClosingFuture.");
                    } catch (IllegalArgumentException expected) {
                    }
                    capturedPeeker.set(peeker);
                    return closeable2;

		}
	}
}

func Test_metacacheReader_peek(t *testing.T) {
	r := loadMetacacheSample(t)
	defer r.Close()
	for i, want := range loadMetacacheSampleNames {
		got, err := r.peek()
		if err == io.EOF {
			break
		}
		if err != nil {
			t.Fatal(err)
		}
		if got.name != want {
			t.Errorf("entry %d, want %q, got %q", i, want, got.name)
		}
		gotObj, err := r.next()

	public static final field EMPTY Lokhttp3/TrailersSource;
	public abstract fun get ()Lokhttp3/Headers;
	public fun peek ()Lokhttp3/Headers;
}

public final class okhttp3/TrailersSource$Companion {
}

public final class okhttp3/TrailersSource$DefaultImpls {
	public static fun peek (Lokhttp3/TrailersSource;)Lokhttp3/Headers;
}

public abstract interface class okhttp3/WebSocket {

            } catch (e: IOException) {
              throw RuntimeException(e)
            }
          }
          return result
        }

        override fun peek(): MockResponse = queueDispatcher.peek()

        override fun close() {
          queueDispatcher.close()
        }
      }
    client =
      client
        .newBuilder()
        .proxy(server.proxyAddress)

## Version 5.1.0

_2025-07-07_

 *  New: `Response.peekTrailers()`. When we changed `Response.trailers()` to block instead of
    throwing in 5.0.0, we inadvertently removed the ability for callers to peek the trailers
    (by catching the `IllegalStateException` if they weren't available). This new API restores that
    capability.

 *  Fix: Don't crash on `trailers()` if the response doesn't have a body. We broke [Retrofit] users

		}
		if contextCanceled(ctx) {
			return ctx.Err()
		}
		for i, r := range readers {
			if errs[i] != nil {
				hasErr++
				continue
			}
			entry, err := r.peek()
			switch err {
			case io.EOF:
				atEOF++
				continue
			case nil:
			default:
				switch err.Error() {
				case errFileNotFound.Error():
					atEOF++
					fnf++
					continue

	public static final field EMPTY Lokhttp3/TrailersSource;
	public abstract fun get ()Lokhttp3/Headers;
	public fun peek ()Lokhttp3/Headers;
}

public final class okhttp3/TrailersSource$Companion {
}

public final class okhttp3/TrailersSource$DefaultImpls {
	public static fun peek (Lokhttp3/TrailersSource;)Lokhttp3/Headers;
}

public abstract interface class okhttp3/WebSocket {