here's how you would create a bitstream with an UART using the "new" API:
```
import logging
import asyncio

from glasgow.hardware.assembly import HardwareAssembly
from glasgow.applet.interface.uart import UARTInterface


logger = logging.getLogger()


async def main():
    assembly = HardwareAssembly()
    uart = UARTInterface(logger, assembly, rx="A0", tx="A1")
    async with assembly:
        await assembly.device.set_voltage("A", 3.3)
        await uart.set_baud(115200)
        await uart.write(b"hello")
        print(bytes(await uart.read(5)))


logging.basicConfig(level=logging.TRACE)
asyncio.run(main())
```