class GdsApi::JsonClient

def self.cache(size=DEFAULT_CACHE_SIZE, ttl=DEFAULT_CACHE_TTL)

creates a cache with a size of 1.
LRUCache doesn't respect a cache size of 0, and instead effectively

header if it is included in the response.
Cache TTL will be overridden for a given request/response by the Expires 
def self.cache(size=DEFAULT_CACHE_SIZE, ttl=DEFAULT_CACHE_TTL)
  @cache ||= LRUCache.new(max_size: size, ttl: ttl)
end