6.9For Each and payload

Inside the For Each scope, the current item becomes what your processors work with conceptually.

Suppose original payload:

[
  {"id": "C001"},
  {"id": "C002"}
]

Inside an iteration, you're dealing with:

{"id": "C001"}

then:

{"id": "C002"}

afterward.

This means you need to understand what state you're preserving and where.