feat: [Spanner] protos for R/W transaction support on multiplexed sessions

Spanner/src/V1/Gapic/SpannerGapicClient.php

@@ -55,6 +55,7 @@
 use Google\Cloud\Spanner\V1\KeySet;
 use Google\Cloud\Spanner\V1\ListSessionsRequest;
 use Google\Cloud\Spanner\V1\ListSessionsResponse;
+use Google\Cloud\Spanner\V1\MultiplexedSessionPrecommitToken;
 use Google\Cloud\Spanner\V1\Mutation;
 use Google\Cloud\Spanner\V1\PartialResultSet;
 use Google\Cloud\Spanner\V1\PartitionOptions;
@@ -534,6 +535,13 @@ public function batchWrite(
      *           request_options struct will not do anything. To set the priority for a
      *           transaction, set it on the reads and writes that are part of this
      *           transaction instead.
+     *     @type Mutation $mutationKey
+     *           Optional. Required for read-write transactions on a multiplexed session
+     *           that commit mutations but do not perform any reads or queries. Clients
+     *           should randomly select one of the mutations from the mutation set and send
+     *           it as a part of this request.
+     *           This feature is not yet supported and will result in an UNIMPLEMENTED
+     *           error.
      *     @type RetrySettings|array $retrySettings
      *           Retry settings to use for this call. Can be a {@see RetrySettings} object, or an
      *           associative array of retry settings parameters. See the documentation on
@@ -558,6 +566,10 @@ public function beginTransaction(
             $request->setRequestOptions($optionalArgs['requestOptions']);
         }
 
+        if (isset($optionalArgs['mutationKey'])) {
+            $request->setMutationKey($optionalArgs['mutationKey']);
+        }
+
         $requestParams = new RequestParamsHeaderDescriptor(
             $requestParamHeaders
         );
@@ -631,6 +643,13 @@ public function beginTransaction(
      *           and 500 ms.
      *     @type RequestOptions $requestOptions
      *           Common options for this request.
+     *     @type MultiplexedSessionPrecommitToken $precommitToken
+     *           Optional. If the read-write transaction was executed on a multiplexed
+     *           session, the precommit token with the highest sequence number received in
+     *           this transaction attempt, should be included here. Failing to do so will
+     *           result in a FailedPrecondition error.
+     *           This feature is not yet supported and will result in an UNIMPLEMENTED
+     *           error.
      *     @type RetrySettings|array $retrySettings
      *           Retry settings to use for this call. Can be a {@see RetrySettings} object, or an
      *           associative array of retry settings parameters. See the documentation on
@@ -670,6 +689,10 @@ public function commit($session, $mutations, array $optionalArgs = [])
             $request->setRequestOptions($optionalArgs['requestOptions']);
         }
 
+        if (isset($optionalArgs['precommitToken'])) {
+            $request->setPrecommitToken($optionalArgs['precommitToken']);
+        }
+
         $requestParams = new RequestParamsHeaderDescriptor(
             $requestParamHeaders
         );