public BootstrapSessionManager getBootstrapSessionManager(PartitionId id) {
    DiskManager diskManager = getDiskManager(id);
    if (diskManager == null) {
      throw new IllegalArgumentException("Failed to find disk manager for partition " + id);
    }
    return diskManager.getBootstrapSessionManager();
  }
@param id the {@link PartitionId} to find the BootstrapSessionManager for.
@return the {@link BootstrapSessionManager} corresponding to the given {@link PartitionId}, or {@code null} if no BootstrapSessionManager was found.
ambry-store/src/main/java/com/github/ambry/store/StorageManager.java