code: public void verify(VerificationData data) {
          AssertionError error = null;
  
          timer.start();
          while (timer.isCounting()) {
              try {
                  delegate.verify(data);
  
                  if (returnOnSuccess) {
                      return;
                  } else {
                      error = null;
                  }
              } catch (MockitoAssertionError e) {
                  error = handleVerifyException(e);
              }
              catch (AssertionError e) {
                  error = handleVerifyException(e);
              }
          }
  
          if (error != null) {
              throw error;
          }
      }
docs: Verify the given ongoing verification data, and confirm that it satisfies the delegate verification mode
  before the full duration has passed.
  
  In practice, this polls the delegate verification mode until it is satisfied. If it is not satisfied once
  the full duration has passed, the last error returned by the delegate verification mode will be thrown
  here in turn. This may be thrown early if the delegate is unsatisfied and the verification mode is known
  to never recover from this situation (e.g. {@link AtMost}).
  
  If it is satisfied before the full duration has passed, behaviour is dependent on the returnOnSuccess parameter
  given in the constructor. If true, this verification mode is immediately satisfied once the delegate is. If
  false, this verification mode is not satisfied until the delegate is satisfied and the full time has passed.
  
  @throws MockitoAssertionError if the delegate verification mode does not succeed before the timeout