protected long snapshotId() {
    if (snapshotId == null) {
      synchronized (this) {
        while (snapshotId == null || ops.current().snapshot(snapshotId) != null) {
          this.snapshotId = ops.newSnapshotId();
        }
      }
    }
    return snapshotId;
  }
@deprecated will be removed in 1.7.0; Use {@link SnapshotProducer#newManifestOutputFile}
    instead
iceberg/patched-iceberg-core/src/main/java/org/apache/iceberg/SnapshotProducer.java