`Actor.MakeUnsignedUncheckedRun` method imposes restriction to
`CalculateNetworkFee` method's implementations: `Hash` or `Size` methods
must not be called on the pointer to the given transaction.
Add docs to adjust described requirement.
Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>
Somewhat similar to invoker, but changing the state (or just creating a
transaction). Transaction creation could've been put into a structure of its
own, but it seems to be less convenient to use this way.
