I have already done a preliminary review for you, and I hope to help you do a better job.

Based on the pull request title and description, the key changes in this pull request are that Tiflash will be built using Rust cargo cache in nightly builds.

One potential problem is that it is not clear what specific version of Rust Cargo cache is being used and if there are any potential compatibility issues with the current system configuration. Another potential problem is that this change may increase the build time if Rust Cargo cache is not already installed and configured properly.

As a fix, the pull request author can provide more details about the specific version of Rust Cargo cache being used and ensure that it is compatible with the current system configuration. They can also provide instructions on how to properly install and configure Rust Cargo cache to avoid any potential build time increases. Additionally, it would be helpful to add some details about the testing that was done to ensure that this change does not introduce any new issues.

[APPROVALNOTIFIER] This PR is APPROVED

Approval requirements bypassed by manually added approval.

This pull-request has been approved by:

The full list of commands accepted by this bot can be found here.

The pull request process is described here