public void append(long timestamp, ByteBuffer key, ByteBuffer value) {
        append(timestamp, key, value, Record.EMPTY_HEADERS);
    }
Append a new record at the next sequential offset.
@param timestamp The record timestamp
@param key The record key
@param value The record value
clients/src/main/java/org/apache/kafka/common/record/MemoryRecordsBuilder.java