how to promote the speed

[haoyuxiaoxue]

thanks for your watching
recently I use this library. I find that the time of read a sbus frame is not stable. sometimes it cost 40ms.I use nonblocking model.the waitFrame function cost too much time and unstable.
how could I promete the reading speed and at the same time make the sbus frame more stable?

timer_1 = micros();
if (!sbus.waitFrame())
{
Serial.println("time out! ");
}
else
{

getChannelSignal();
processSignal(receiver_input_channel[4], n);
n++;
if (n > (USED_NUM - 1))n -= USED_NUM;
//printChannelSignal();
checkSBUS();
generate_pwm();

}
timer_2 = micros();
Serial.println(timer_2 - timer_1);

the output
19744
19756
19752
19756
42664
34736
19756
35492
55616
19752
19748
19756
23476