JIRA: [NEMO-217: Immediately emits elements in FlattenTransform](https://issues.apache.org/jira/projects/NEMO/issues/NEMO-217)
**Major changes:** - remove `ArrayList` that collects elements in `FlattenTransform` and directly emit the elements **Minor changes to note:** - **Tests for the changes:** - **Other comments:** - Closes #GITHUB_PR_NUMBER [ Full content available at: https://github.com/apache/incubator-nemo/pull/120 ] This message was relayed via gitbox.apache.org for [email protected]
