Running Stepper motors (at least 2) at the same time Is there a way to run a Stepper motor with Arduino MEGA 2560 with A4988 driver component.

I am using this https://github.com/laurb9/StepperDriver library and with this code, 

Serial.println("Starting motor ALL");
int steps = atoi(third.c_str());
int duration = atoi(fourth.c_str());

BasicStepperDriver stepper1(steps, DIR, STEP, ENBL);
stepper1.enable();
stepper1.setMicrostep(MICROSTEPS);
stepper1.setRPM(MAX_RPM);

BasicStepperDriver stepper2(steps, DIR_2, STEP_2, ENBL_2);
stepper2.enable();
stepper2.setMicrostep(MICROSTEPS);
stepper2.setRPM(MAX_RPM);

int starttime = millis();
int endtime = starttime;
while ((endtime - starttime) &lt;= duration) // mS
{
     stepper1.rotate(90);  
     stepper2.rotate(90);  
     endtime = millis();
}
stepper1.disable();
stepper2.disable();
Serial.println("DONE");


The problem with this is that each stepper motor in this code waits for each other and not simultaneously like a DC motor. What could be done to make it work simultaneously?
Try the AccelStepper library. It can control both steppers at the same time. Also provides some useful examples

AccelStepper with more than one stepper also requires the Adafruit Motor library to be installed.