Hi there, I would like to use apache arrow execution engine for some computation. I found `ExecBatch` instead of `RecordBatch` is used for execution engine's node, and I wonder how I can attach some additional information such as schema/metadata for the `ExecBatch` during execution so that they can be used by a custom ExecNode.
In my first use case, the computation flow looks like this: scanner <===> custom filter node <===> query client 1) The scanner is a custom scanner that will load some data from disk, and it accepts a pushed down custom filter expression (not the arrow filter expression but a homebrewed filter expression), and the scanner will use this custom filter expression to avoid loading data from disk as much as possible but it may return a superset of matching data to the successor nodes because the capability of pushed down filter. 2) And its successor node is a filter node, which will do some additional filtering if needed. The scanner is aware that if a result batch retrieved needs additional filtering or not, and I would like to make scanner pass some batch specific metadata like "additional_filtering_required: true/false" along with the batch to the filter node, but I cannot figure out how this could be done for the `ExecBatch`. In my other use case, I would like to attach a batch specific schema to each batch returned by some nodes. Basically, I wonder within the current framework, if there is any chance I could attach some additional execution metadata/schema to the `ExecBatch` so that they could be used by a custom exec node. Could you please help? Thanks.
