src/com/wentch/redkale/convert/bson/BsonByteBufferWriter.java

@@ -21,6 +21,7 @@ public final class BsonByteBufferWriter extends BsonWriter {
     private int index;
 
     public BsonByteBufferWriter(Supplier<ByteBuffer> supplier) {
+        super((byte[]) null);
         this.supplier = supplier;
     }
 

src/com/wentch/redkale/convert/bson/BsonWriter.java

@@ -49,6 +49,10 @@ public class BsonWriter implements Writer {
         return len;
     }
 
+    protected BsonWriter(byte[] bs) {
+        this.content = bs;
+    }
+
     public BsonWriter() {
         this(defaultSize);
     }