Copying a column to a SSIS package variable

I need to use a value retrieved in one data flow in the second data flow. What's the best way to do this?

How do I copy the column retrieved to a variable so I can use that variable in the second data flow?

Data Flow implies multiple rows, which doesn't naturally fit with a single variable.

Normally I would be using an Exec SQL Task to populate a variable from a table. You could use a Script Component in the data flow, or perhaps the Recordset Destination if there are several rows.

If reading just one value/line from a file for example, then I'd just use the Script Task.