What is the proper implementation for using ETags when making API requests to the Weather.com API, and how does it impact bandwidth usage?

Proper implementation for using ETags when making API requests to the Weather.com API involves caching the ETag value received in the response header from the initial request and then including it in the 'If-None-Match' request header for subsequent requests. 'ETags' (Entity Tags) are HTTP response headers that provide a unique identifier for a specific version of a resource. They allow clients to make conditional requests, reducing bandwidth usage by only downloading the resource if it has changed since the last request. When making an initial request to the Weather.com API, the response header should be inspected for an ETag value. This value should be stored locally (e.g., in a database, cache, or cookie). For subsequent requests to the same resource, the stored ETag value should be included in the 'If-None-Match' request header. For example, if the initial response header contains 'ETag: "1234567890"', subsequent requests should include the header 'If-None-Match: "1234567890"'. When the Weather.com API receives a request with an 'If-None-Match' header, it compares the provided ETag value to the current ETag value for the requested resource. If the ETag values match, meaning the resource has not changed since the last request, the API returns an HTTP 304 Not Modified response. This response does not include the resource data, only the header, which is much smaller than the full resource data. If the ETag values do not match, meaning the resource has been updated since the last request, the API returns an HTTP 200 OK response with the updated resource data and a new ETag value. By using ETags, the application can avoid downloading the same weather data multiple times if it has not changed, significantly reducing bandwidth usage. This is particularly beneficial for mobile devices with limited bandwidth or data plans. If the application receives a 304 Not Modified response, it should use the cached weather data and update its local ETag value with the value from the 304 response (if provided). If the application receives a 200 OK response, it should replace its cached weather data with the new data and update its local ETag value with the new ETag value from the response. Improper implementation, such as ignoring the ETag or not sending the 'If-None-Match' header, negates the bandwidth-saving benefits of ETags.