100 Continue
Explanation:
The 100 Continue informational status code indicates that the initial part of a request has been received and has not yet been rejected by the server. The server intends that the client should continue sending the remainder of the request or, if the request has already been completed, ignore this response. The ultimate response to the request is separate from the status code 100.
Usage:
This status code is used to inform the client that the initial part of the request has been received, and they should continue with the rest of the request or ignore the message if the request is already complete.
Attentions:
- This status code is part of the HTTP/1.1 specification and is sent when the server wishes to improve network efficiency by confirming that large requests are necessary before the client sends them.
- The client must be prepared to discard this preliminary status and wait for the final response.
- Clients that cannot process a 100 Continue response should not include the `Expect: 100-continue` header in requests.
Sample: