NewClient constructs a new client with the provided options (ex WithTimeout).

WithTimeout sets the .Timeout attribute of the wrapped http.Client.

ErrNotFound specifically means that a '404 - NOT FOUND' response was received from the API.

ErrNotOK is used to indicate when an HTTP request to the Beacon Node API failed with any non-2xx response code.

Client provides a collection of helper methods for calling Builder API endpoints.

ClientOpt is a functional option for the Client type (http.Client wrapper).