Endpoint is the endpoint object returned by Endpoint resolution V2
type Endpoint struct {
// The complete URL minimally specfiying the scheme and host.
// May optionally specify the port and base path component.
URI url.URL
// An optional set of headers to be sent using transport layer headers.
Headers http.Header
// A grab-bag property map of endpoint attributes. The
// values present here are subject to change, or being add/removed at any
// time.
Properties smithy.Properties
}