PaperMC/nms-patches/DamageSource.patch

--- a/net/minecraft/server/DamageSource.java
+++ b/net/minecraft/server/DamageSource.java
@@ -35,6 +35,18 @@
     private boolean D;
     private boolean E;
     public final String translationIndex;
+    // CraftBukkit start
+    private boolean sweep;
+
+    public boolean isSweep() {
+        return sweep;
+    }
+
+    public DamageSource sweep() {
+        this.sweep = true;
+        return this;
+    }
+    // CraftBukkit end
 
     public static DamageSource mobAttack(EntityLiving entityliving) {
         return new EntityDamageSource("mob", entityliving);