Function probe_terminal 

pub fn probe_terminal(
    tty: &mut (impl Read + Write),
    timeout: Duration,
) -> ProbeResults

Performs a blocking startup capability probe.

The terminal must already be in raw mode. To make the deadline effective, tty must return io::ErrorKind::WouldBlock or io::ErrorKind::TimedOut while no input is available. Returned ProbeResults::preserved_input must be delivered to the application’s normal input pipeline before newly read input. Terminal I/O errors end the probe conservatively and leave environment fallback resolution available.