pub unsafe extern "system" fn DRMGetSignedIssuanceLicense(
    henv: u32,
    hissuancelicense: u32,
    uflags: u32,
    pbsymkey: *mut u8,
    cbsymkey: u32,
    wszsymkeytype: PCWSTR,
    wszclientlicensorcertificate: PCWSTR,
    pfncallback: DRMCALLBACK,
    wszurl: PCWSTR,
    pvcontext: *mut c_void
) -> HRESULT