pub fn with_rx(mut self, rx: impl PeripheralInput<'d>) -> Self {
        self.rx = self.rx.with_rx(rx);
        self
    }
Assign the RX pin for UART instance.

Sets the specified pin to input and connects it to the UART RX signal.

Note: when you listen for the output of the UART peripheral, you should
configure the driver side (i.e. the TX pin), or ensure that the line is
initially high, to avoid receiving a non-data byte caused by an
initial low signal level.
esp-hal/src/uart.rs