https://github.com/googleapis/google-cloud-java/blob/master/google-cloud-clients/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/stub/SpannerStubSettings.java#L445

provides retry settings for methods. These should be relied on as they are kept in sync between the different client libraries.

Currently these constants are being used and should likely instead reference the configs https://github.com/googleapis/google-cloud-java/blob/master/google-cloud-clients/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerImpl.java#L62