protected void decodeInto(PutDocumentMessage msg, DocumentDeserializer buf) {
            msg.setDocumentPut(new DocumentPut(Document.createDocument(buf)));
            msg.setTimestamp(buf.getLong(null));
            decodeTasCondition(msg, buf);
            if (buf.getBuf().hasRemaining()) {
                byte value = buf.getBuf().get();
                msg.setCreateIfNonExistent(value != 0);
            }
        }
This method decodes a reply from the given byte buffer. You are guaranteed to only receive byte buffers
generated by a previous call to {@link #doEncode(DocumentReply, com.yahoo.document.serialization.DocumentSerializer)}.

<p>
This method is NOT exception safe. Return null to signal failure.

@param buf The byte buffer to read from.
@return The decoded reply.
documentapi/src/main/java/com/yahoo/documentapi/messagebus/protocol/RoutableFactories60.java