Dataflow Templates uses Code Owners to manage code review. This means that for some PRs, reviewers will be automatically assigned. Code Owners are configured from the CODEOWNERS file.
The goal is for this to eventually be fully automated, it is not yet, however,
for certain directories. If you create a PR and a reviewer is not assigned
within 1 business day, please tag @GoogleCloudPlatform/dataflow-templates-wg
on your PR to get a reviewer assigned.