The collation generation subsystem is the interface between polkadot and the collators.

Protocol

On every ActiveLeavesUpdate:

• If there is no collation generation config, ignore.
• Otherwise, for each activated head in the update:
  • Determine if the para is scheduled on any core by fetching the availability_cores Runtime API.
  • Use the Runtime API subsystem to fetch the full validation data.
  • Invoke the collator, and use its outputs to produce a CandidateReceipt, signed with the configuration's key.
  • Dispatch a CollatorProtocolMessage::DistributeCollation(receipt, pov).