Function get_imsi 

pub unsafe extern "C" fn get_imsi(
    handle: ClientHandle,
    app_info: *mut AppIdInfo,
    imsi: *mut c_char,
    imsi_len: usize,
) -> ErrorCode

Available on non-ag35 only.

Sends a command to the modem to retrieve the IMSI (for 3GPP) or IMSI_M (for 3GPP2) from the SIM in ASCII form.