port = await navigator.serial.requestPort()
await port.open({baudRate: 115200})
await port.close()
port.readable_
port.readable.locked
window.readable = port.readable
window.readable.locked
port.writable_
port.writable.locked
reader = port.readable.getReader()
reader.closed
reader.cancel()
reader.releaseLock()
await reader.read()