```ruby
# --- BEGIN LICENSE_HEADER BLOCK ---
# Copyright 2011-2013, The Trustees of Indiana University and Northwestern
#   University.  Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
# 
# You may obtain a copy of the License at
# 
# http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing, software distributed 
#   under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
#   CONDITIONS OF ANY KIND, either express or implied. See the License for the 
#   specific language governing permissions and limitations under the License.
# ---  END LICENSE_HEADER BLOCK  ---

require 'avalon/workflow/workflow_datastream'

module Avalon::Workflow
  module WorkflowModelMixin
    def self.included(klazz)
      klazz.has_metadata name: 'workflow', type: WorkflowDatastream
    end
  end
end
```

Use Hydra 10 style datastream declaration
user
```ruby
# --- BEGIN LICENSE_HEADER BLOCK ---
# Copyright 2011-2013, The Trustees of Indiana University and Northwestern
#   University.  Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
# 
# You may obtain a copy of the License at
# 
# http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing, software distributed 
#   under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
#   CONDITIONS OF ANY KIND, either express or implied. See the License for the 
#   specific language governing permissions and limitations under the License.
# ---  END LICENSE_HEADER BLOCK  ---

require 'avalon/workflow/workflow_datastream'

module Avalon::Workflow
  module WorkflowModelMixin
    def self.included(klazz)
      klazz.has_subresource 'workflow', class_name: 'WorkflowDatastream'
    end
  end
end
```
assistant