Add Variant in OriginalType

Author: aihuaxu

parquet-column/src/main/java/org/apache/parquet/schema/LogicalTypeAnnotation.java

@@ -260,6 +260,8 @@ public static LogicalTypeAnnotation fromOriginalType(OriginalType originalType,
         return bsonType();
       case MAP_KEY_VALUE:
         return MapKeyValueTypeAnnotation.getInstance();
+      case VARIANT:
+        return variantType();
       default:
         throw new RuntimeException(
             "Can't convert original type to logical type, unknown original type " + originalType);
@@ -1148,8 +1150,7 @@ private VariantLogicalTypeAnnotation() {}
 
     @Override
     public OriginalType toOriginalType() {
-      // No OriginalType for Variant
-      return null;
+      return OriginalType.VARIANT;
     }
 
     @Override

parquet-column/src/main/java/org/apache/parquet/schema/OriginalType.java

@@ -44,5 +44,6 @@ public enum OriginalType {
   INT_64,
   JSON,
   BSON,
-  INTERVAL
+  INTERVAL,
+  VARIANT
 }