Function nanocoap_cache_key_lookup

pub unsafe extern "C" fn nanocoap_cache_key_lookup(
    cache_key: *const u8,
) -> *mut nanocoap_cache_entry_t

@brief Performs a cache lookup based on the cache key of a request.

@param[in] cache_key The cache key of a request

@return An existing cache entry on cache hit @return NULL on cache miss