某些人在某一个特定的时机热烈主张某一特定的正义，其中隐藏着深不可测的不正义。 –龙应台
the lambda architecture
reference
- https://en.wikipedia.org/wiki/Lambda_architecture
- https://mapr.com/resources/stream-processing-mapr/
- http://lambda-architecture.net/
- https://towardsdatascience.com/lambda-architecture-how-to-build-a-big-data-pipeline-part-1-8b56075e83fe
- https://medium.com/walmartlabs/how-we-built-a-data-pipeline-with-lambda-architecture-using-spark-spark-streaming-9d3b4b4555d3