public static byte[] createCompositeKey(String tableName, ImmutableBytesWritable suffix) {
    return combineTableNameSuffix(tableName.getBytes(Charset.forName("UTF-8")), suffix.get());
  }
Alternate api which accepts a String for the tableName and ImmutableBytesWritable for the
suffix
@see MultiTableHFileOutputFormat#createCompositeKey(byte[], byte[])
hbase-mapreduce/src/main/java/org/apache/hadoop/hbase/mapreduce/MultiTableHFileOutputFormat.java