A custom `HttpClient` for use with `fetch` function. This is designed to allow custom certificates or proxies to be used with `fetch()`.

Create a custom HttpClient to use with `fetch`. This is an extension of the web platform Fetch API which allows Deno to use custom TLS CA certificates and connect via a proxy while using `fetch()`. The `cert` and `key` options can be used to specify a client certificate and key to use when connecting to a server that requires client authentication (mutual TLS or mTLS). The `cert` and `key` options must be provided in PEM format.

Basic authentication credentials to be used with a [`Deno.Proxy`](./././~/Deno.Proxy) server when specifying [`Deno.CreateHttpClientOptions`](./././~/Deno.CreateHttpClientOptions).

The options used when creating a [`Deno.HttpClient`](./././~/Deno.HttpClient).

The definition of a proxy when specifying [`Deno.CreateHttpClientOptions`](./././~/Deno.CreateHttpClientOptions).