public static boolean supportsAggregationBufferSchema(StructType schema) {
        for (StructField field : schema.fields()) {
            if (!UnsafeRow.isMutable(field.dataType())) {
                return false;
            }
        }
        return true;
    }
@return true if UnsafeFixedWidthAggregationMap supports aggregation buffers with the given
schema, false otherwise.
indexr-query-opt/src/main/java/org/apache/spark/sql/execution/UnsafeFixedWidthAggregationMap.java