mainloop: Use sdeventplus

Convert to using sdeventplus instead of sd_event directly.

Change-Id: Ie8ee25c2d75ac4c56b88fb79f70eaa53c4f7b6e4
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/mainloop.hpp b/mainloop.hpp
index 9c50c78..87f6ed0 100644
--- a/mainloop.hpp
+++ b/mainloop.hpp
@@ -12,6 +12,7 @@
 #include <memory>
 #include <optional>
 #include <sdbusplus/server.hpp>
+#include <sdeventplus/event.hpp>
 #include <string>
 #include <vector>
 
@@ -99,8 +100,8 @@
     hwmonio::HwmonIO ioAccess;
     /** @brief Timer */
     std::unique_ptr<phosphor::hwmon::Timer> timer;
-    /** @brief the sd_event structure */
-    sd_event* loop = nullptr;
+    /** @brief the Event Loop structure */
+    sdeventplus::Event event;
     /** @brief Store the specifications of sensor objects */
     std::map<SensorSet::key_type, std::unique_ptr<sensor::Sensor>>
         sensorObjects;