public Builder mergeRdbSnapshotStartTime(com.google.protobuf.Timestamp value) {
        if (rdbSnapshotStartTimeBuilder_ == null) {
          if (((bitField0_ & 0x00000002) != 0)
              && rdbSnapshotStartTime_ != null
              && rdbSnapshotStartTime_ != com.google.protobuf.Timestamp.getDefaultInstance()) {
            getRdbSnapshotStartTimeBuilder().mergeFrom(value);
          } else {
            rdbSnapshotStartTime_ = value;
          }
        } else {
          rdbSnapshotStartTimeBuilder_.mergeFrom(value);
        }
        if (rdbSnapshotStartTime_ != null) {
          bitField0_ |= 0x00000002;
          onChanged();
        }
        return this;
      }
<pre>
Optional. Time that the first snapshot was/will be attempted, and to
which future snapshots will be aligned. If not provided, the current time
will be used.
</pre>

<code>
.google.protobuf.Timestamp rdb_snapshot_start_time = 2 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-valkey/proto-google-cloud-valkey-v1beta/src/main/java/com/google/cloud/memorystore/v1beta/PersistenceConfig.java