case sigIdle:
				if sig.state.CompareAndSwap(sigIdle, sigReceiving) {
					if GOOS == "darwin" || GOOS == "ios" {
						sigNoteSleep(&sig.note)
						break Receive
					}
					notetsleepg(&sig.note, -1)
					noteclear(&sig.note)
					break Receive
				}
			case sigSending:
				if sig.state.CompareAndSwap(sigSending, sigIdle) {
					break Receive
				}
			}
		}

		// Return or sleep according to mode.
		if mode == profBufNonBlocking {
			// Necessary on Darwin, notetsleepg below does not work in signal handler, root cause of #61768.
			return nil, nil, false
		}
		if !b.w.cas(bw, bw|profReaderSleeping) {
			goto Read
		}
		// Committed to sleeping.
		notetsleepg(&b.wait, -1)
		noteclear(&b.wait)
		goto Read
	}
	data = b.data[br.dataCount()%uint32(len(b.data)):]