static {
   registerAllocationCommand(
       CancelAllocationCommand::new,
       CancelAllocationCommand::fromXContent,
       CancelAllocationCommand.COMMAND_NAME_FIELD);
   registerAllocationCommand(
       MoveAllocationCommand::new,
       MoveAllocationCommand::fromXContent,
       MoveAllocationCommand.COMMAND_NAME_FIELD);
   registerAllocationCommand(
       AllocateReplicaAllocationCommand::new,
       AllocateReplicaAllocationCommand::fromXContent,
       AllocateReplicaAllocationCommand.COMMAND_NAME_FIELD);
   registerAllocationCommand(
       AllocateEmptyPrimaryAllocationCommand::new,
       AllocateEmptyPrimaryAllocationCommand::fromXContent,
       AllocateEmptyPrimaryAllocationCommand.COMMAND_NAME_FIELD);
   registerAllocationCommand(
       AllocateStalePrimaryAllocationCommand::new,
       AllocateStalePrimaryAllocationCommand::fromXContent,
       AllocateStalePrimaryAllocationCommand.COMMAND_NAME_FIELD);
   namedWriteables.add(
       new NamedWriteableRegistry.Entry(
           Task.Status.class, ReplicationTask.Status.NAME, ReplicationTask.Status::new));
   namedWriteables.add(
       new NamedWriteableRegistry.Entry(
           Task.Status.class, RawTaskStatus.NAME, RawTaskStatus::new));
 }