For DLQ messages that have a "doc" field, the doc._stream_meta will be set, and there is also a top level _stream_meta field.

{
  _stream_meta: ...,
  errInfo: { reason: ... },
  doc: {
    device_id: '',
    _ts: ...,
    _stream_meta: ...
  }
}

Note that some DLQ messages do not have an associated input doc, their schema looks like:

{
  
  _stream_meta: ...,
  errInfo: { reason: ... }
  // no doc field
}