reduce Lambda invocations

[bernard357]

What is this?

Here we fine-tune the EventBridge rules to prevent useless invocations

Why is this important?

Since Lambda invocations increase linearly with the number of accounts that SPA manages, it is important to maintain these invocations to a very minimum.

How to implement it?

• only use events that begin or end transactions to trigger the metering Lambda - other events are useless
• only use expiration events from DynamoDB to trigger transaction time outs - other DynamoDB events are useless