Function apps_slash_create_from_manifest 

pub async fn apps_slash_create_from_manifest(
    configuration: &Configuration,
    code: &str,
) -> Result<AppsCreateFromManifest201Response, Error<AppsSlashCreateFromManifestError>>

Use this endpoint to complete the handshake necessary when implementing the GitHub App Manifest flow. When you create a GitHub App with the manifest flow, you receive a temporary code used to retrieve the GitHub App’s id, pem (private key), and webhook_secret.