Stream to Block Node's immediately instead of when BlockProof is produced

[derektriley]

Background

Currently an entire block is buffered in memory until the BlockProof is produced, at that point then the Consensus Node will stream the block in batches to each Block Node it's connected to.

In order to minimize latency, the Consensus Node should immediately stream block items (still respecting the configurable batch size and chronological ordering) to Block Nodes.

Acceptance Criteria

• Stream to Block Node's immediately instead of waiting for the BlockProof to be produced
• Immediately but we need to wait/buffer until we have enough items to fulfill the configurable batch size.
• Need to maintain chronological ordering of block items, i.e. don't immediately stream block 2's items until we've streamed the BlockProof for block 1.

Dependencies

#17730

Definition of Ready (DoR) Checklist

• Clear acceptance criteria
• Clear and detailed description
• Dependencies identified
• Links to documentation
• Should be completable in 2-3 Days
• Initial draft of Low-level design document
• At least high level test plan
• Groomed/Estimated

Definition of Done (DoD) Checklist

• Acceptance Criteria complete
• No Codacy issues greater than minor (in new code)
• JavaDocs updated/created
• Code commented
• Unit tests created/updated
• 80% test code coverage (in new code)
• Happy Path and major negative cases in HAPI tests as applicable