Elasticsearch recently added the possibility to store meta field information.

We should add support in ECS tooling to start specifying this information, for fields where this applies. The initial proposal is to start defining the following, but more may come:

• unit: s (seconds)
• unit: B (bytes)
• format: pct

Tasks:

• Add support in the ECS generator
• Populate meta/unit for all fields where it makes sense

I don't think ECS has a field that tracks percentages at this time. But if it does, we should populate it as well.