Understanding Flow when Collecting Signatures from Multiple Nodes

Until CE/COS 4.4, when collecting signatures from multiple nodes, Flow APIs were implemented to collect signatures sequentially, raising the latency of collecting signatures from many nodes.
In contrast, CE/COS 4.5 adds the ability to collect signatures from each node in parallel (SendAll/SendAllMap) if there are multiple nodes to be signed (requiredSigner) to reduce latency concerns when collecting signatures from multiple nodes that were feared in CE/COS 4.4 and earlier.
For more information, please refer to the official documentation below.

https://docs.corda.net/docs/corda-enterprise/4.8/cordapps/api-flows.html#communication-between-parties