+------------+-----------------------------------------------------+
  |            |                        Message                      |
  |            |----------+-------------+-------------+--------------|
  |            |          |             |             |              |
  | Signatures |          |  Account    |  Recent     |              |
  |            |  Header  |  addresses  |  blockhash  | Instructions |
  |            |          |             |             |              |
  +------------+----------+-------------+-------------+--------------+