RTIC incompatibility

[TomSievers]

I've been trying to use this library with RTIC and ran into an issue.

The issue resides in using the modem in an RTIC task with a priority > 0. I created a repo with a two runnable examples at https://github.com/TomSievers/rtic-nrf-modem. One example shows that the modem can be used with RTIC, the other shows it not working in an interrupt context.

When initializing the modem at priority > 0 it will fail with the NRF error code of -116 (NRF_ETIMEDOUT). If the modem is succesfully initialized and afterwards one tries to bind a UdpSocket it fails with NRF error code of -1 (NRF_EPERM).

Maybe these functions are designed in a way where they will not work from an interrupt context.

I will look into trying this with the libmodem_log instead of the default libmodem to get more info into why it fails.