MessagePacker
The message packer returned by the MessagePackerInstructionPlan.
It offers a packMessageToCapacity(transactionMessage)
method that packs as many instructions
as possible into the provided transaction message, while still being able to fit into the
transaction size limit. It returns the updated transaction message with the packed instructions
or throws an error if the current transaction message cannot accommodate this plan.
The done()
method checks whether there are more instructions to pack into
transaction messages.