"File Source" to "Packet Tx" connection

Hi all,

I want to connect a "File Source" to "Packet Tx" (the hier block).
I wonder what the best practice is.

The deprecated "Packet Encoder" got streams as input, but the new "Packet Encoder" just gets

messages.

versions:
    Ubuntu 22.04
    GR 3.10.11.0

Thank you!