amountSatoshis property
What the recording says the transaction paid, read off the journaled event.
Null is an absence, not a zero (spv-understanding.md: the library must not manufacture state it cannot evidence). It is null when this command journaled nothing because the wallet had recorded the transaction already (bead libspiffy-viy), so there is no event this announcement can read the amount off. The recording still stands — success says so — and the amount is on the transaction the queries return.
Implementation
final BigInt? amountSatoshis;