Function echo_can_update 

pub unsafe extern "C" fn echo_can_update(
    ec: *mut echo_can_state_t,
    tx: i16,
    rx: i16,
) -> i16

Process a sample through a voice echo canceller. \param ec The echo canceller context. \param tx The transmitted audio sample. \param rx The received audio sample. \return The clean (echo cancelled) received sample.