fix: increase sample row key default timeout for beam (#4567)

Change-Id: I004f0881e24600e14a37cf62a78b8e341edc70ed

Author: mutianf

bigtable-dataflow-parent/bigtable-hbase-beam/src/main/java/com/google/cloud/bigtable/batch/common/CloudBigtableServiceImpl.java

@@ -24,6 +24,7 @@
 import com.google.cloud.bigtable.beam.CloudBigtableTableConfiguration;
 import com.google.cloud.bigtable.hbase.wrappers.veneer.BigtableHBaseVeneerSettings;
 import java.io.IOException;
+import java.time.Duration;
 import java.util.List;
 
 /** For internal use only - public for technical reasons. */
@@ -52,6 +53,15 @@ public List<KeyOffset> getSampleRowKeys(CloudBigtableTableConfiguration config)
                         .setPreemptiveRefreshEnabled(false)
                         .build())
                 .build());
+
+    builder
+        .stubSettings()
+        .sampleRowKeysSettings()
+        .retrySettings()
+        .setInitialRpcTimeoutDuration(Duration.ofMinutes(20))
+        .setMaxRpcTimeoutDuration(Duration.ofMinutes(20))
+        .setTotalTimeoutDuration(Duration.ofMinutes(20));
+
     try (BigtableDataClient client = BigtableDataClient.create(builder.build())) {
       return client.sampleRowKeys(config.getTableId());
     }