Add exception reporting event

paper-server/src/main/java/com/destroystokyo/paper/ServerSchedulerReportingWrapper.java

@@ -0,0 +1,38 @@
+package com.destroystokyo.paper;
+
+import com.google.common.base.Preconditions;
+import org.bukkit.craftbukkit.scheduler.CraftTask;
+import com.destroystokyo.paper.event.server.ServerExceptionEvent;
+import com.destroystokyo.paper.exception.ServerSchedulerException;
+
+/**
+ * Reporting wrapper to catch exceptions not natively
+ */
+public class ServerSchedulerReportingWrapper implements Runnable {
+
+    private final CraftTask internalTask;
+
+    public ServerSchedulerReportingWrapper(CraftTask internalTask) {
+        this.internalTask = Preconditions.checkNotNull(internalTask, "internalTask");
+    }
+
+    @Override
+    public void run() {
+        try {
+            internalTask.run();
+        } catch (RuntimeException e) {
+            internalTask.getOwner().getServer().getPluginManager().callEvent(
+                    new ServerExceptionEvent(new ServerSchedulerException(e, internalTask))
+            );
+            throw e;
+        } catch (Throwable t) {
+            internalTask.getOwner().getServer().getPluginManager().callEvent(
+                    new ServerExceptionEvent(new ServerSchedulerException(t, internalTask))
+            ); //Do not rethrow, since it is not permitted with Runnable#run
+        }
+    }
+
+    public CraftTask getInternalTask() {
+        return internalTask;
+    }
+}