got it so that reading usb packets reliably works "sometimes"
diff --git a/aos/common/time.h b/aos/common/time.h
index ea703f7..276cf1c 100644
--- a/aos/common/time.h
+++ b/aos/common/time.h
@@ -160,6 +160,8 @@
   const Time operator-(const Time &rhs) const;
   const Time operator*(int32_t rhs) const;
   const Time operator/(int32_t rhs) const;
+  // TODO(brians) test this
+  double operator/(const Time &rhs) const;
   const Time operator%(int32_t rhs) const;
 
   bool operator==(const Time &rhs) const;