BadRequest error response is supposed to be sent to the client on bad request error.

InternalError error response is supposed to be sent to the client on internal error.

Ok response is supposed to be sent to the client on success.

Unauthorized error response is supposed to be sent to the client on unauthorized error.

Error structure provides the most basic error payload sent to the client.

Message structure provides the most basic payload with message sent to the client.

Writer structure is a wrapper around http.ResponseWriter.