Function otPlatDnsCancelUpstreamQuery 

pub unsafe extern "C" fn otPlatDnsCancelUpstreamQuery(
    aInstance: *mut otInstance,
    aTxn: *mut otPlatDnsUpstreamQuery,
)

Cancels a transaction of upstream query.

The platform must call otPlatDnsUpstreamQueryDone to release the resources.

@param[in] aInstance The OpenThread instance structure. @param[in] aTxn A pointer to the opaque DNS query transaction object.