feat(spanner): add change streams transaction exclusion sample

[ShuranZhang]

Add sample for how to configure change streams transaction exclusion in various write APIs.

Note: the current latest release of spanner go client library does not contain the source code change in googleapis/google-cloud-go#9779 yet, so there will be build failures in CI/CD. However I have verified that all IT tests passed after pointing the go client dependency to my newest local cloned copy.

This pr will not be merged until the latest go client release contains the necessary source code change, just uploading it now to kick off the review process earlier.

[snippet-bot]

Here is the summary of changes.

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• spanner/spanner_snippets/spanner/spanner_change_streams_txn_exclusion.go:17, tag spanner_set_exclude_txn_from_change_streams

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[muncus]

CI is still reporting failures:

    integration_test.go:1167: failed to commit rw txn excluded from change streams: spanner: code = "Unimplemented", desc = "ExcludeTxnFromChangeStreams is not enabled."
    integration_test.go:418: got output ""; want it to contain "New singer inserted."
    integration_test.go:419: got output ""; want it to contain "Singer first name updated."
    integration_test.go:1167: failed to apply mutations excluded from change streams: spanner: code = "Unimplemented", desc = "ExcludeTxnFromChangeStreams is not enabled."
    integration_test.go:421: got output ""; want it to contain "New singer inserted."
    integration_test.go:1167: failed to apply at least once mutations excluded from change streams: spanner: code = "Unimplemented", desc = "ExcludeTxnFromChangeStreams is not enabled."
    integration_test.go:423: got output ""; want it to contain "New singer inserted."
    integration_test.go:1167: failed to write data using BatchWrite excluded from change streams: rpc error: code = Unimplemented desc = ExcludeTxnFromChangeStreams is not enabled.
    integration_test.go:1167: failed to update using partitioned DML excluded from change streams: spanner: code = "Unimplemented", desc = "ExcludeTxnFromChangeStreams is not enabled."
    integration_test.go:427: got output ""; want it to contain "record(s) updated"

Is this expected? (or do we just need to update the client library version?)

We should hold off merging this until CI passes, as we do not want to have broken samples included in our documentation. please let me know how you'd like to proceed.

[ShuranZhang]

CI is still reporting failures:

    integration_test.go:1167: failed to commit rw txn excluded from change streams: spanner: code = "Unimplemented", desc = "ExcludeTxnFromChangeStreams is not enabled."
    integration_test.go:418: got output ""; want it to contain "New singer inserted."
    integration_test.go:419: got output ""; want it to contain "Singer first name updated."
    integration_test.go:1167: failed to apply mutations excluded from change streams: spanner: code = "Unimplemented", desc = "ExcludeTxnFromChangeStreams is not enabled."
    integration_test.go:421: got output ""; want it to contain "New singer inserted."
    integration_test.go:1167: failed to apply at least once mutations excluded from change streams: spanner: code = "Unimplemented", desc = "ExcludeTxnFromChangeStreams is not enabled."
    integration_test.go:423: got output ""; want it to contain "New singer inserted."
    integration_test.go:1167: failed to write data using BatchWrite excluded from change streams: rpc error: code = Unimplemented desc = ExcludeTxnFromChangeStreams is not enabled.
    integration_test.go:1167: failed to update using partitioned DML excluded from change streams: spanner: code = "Unimplemented", desc = "ExcludeTxnFromChangeStreams is not enabled."
    integration_test.go:427: got output ""; want it to contain "record(s) updated"

Is this expected? (or do we just need to update the client library version?)

We should hold off merging this until CI passes, as we do not want to have broken samples included in our documentation. please let me know how you'd like to proceed.

Hi! Sorry for the confusion, I just converted this cl into a draft. Yes this is expected since this feature is still under limited visibility. I'll re-open this pr once this feature is turned on by default in production. Thanks!