fix(core): pipeline doesn’t stop automatically after all registered datasources complete

[kalloc]

Observed a case where the pipeline continues running even after all datasources have finished their work.
For example, when using RpcBlockCrawler with a defined end_slot, the pipeline does not terminate automatically upon reaching the end.

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From Deluge with love!

[kalloc]

@sonicfromnewyoke hi, I found that the RPC block crawler datasource does not exit after complete crawling. I wrote a reproductive example (also maybe possible as just example) and resolved the issue.
Moreover, I removed referencing to a sender channel (&sender) in datasources because moving or .clone is enough, channel already based on Arc. If you do not agree with it, I can return.

[sonicfromnewyoke]

wow, this is huge 🤩
run lt locally, everything works good

[sonicfromnewyoke]

@kalloc thank you for the so precise debug and fix 💪

[DerZwergGimli]

can we make sure this is in a new version maybe 0.8.2 since using crates.io

[cargo.toml]

carbon-core = 0.8.1
carbon-rpc-block-crawler-datasource = 0.8.1

still gives the described issue (the Pipeline won't stop - only referencing the git repo resolves this)

[cargo.toml]

carbon-core = { git = "https://github.com/sevenlabs-hq/carbon", version = "0.8.1" }
carbon-rpc-block-crawler-datasource = { git = "https://github.com/sevenlabs-hq/carbon", version = "0.8.1" }