lib4.go

package mylib

import "net/http"

// New create a new Instance of mylib
func New(someAlwaysRequiredValue string) (*Builder, error) {
	return &Builder{
		// some nice sane defaults if necessary
	}, nil
}

// Builder configures Instance to be built
type Builder struct {
	username string
	password string
}

// BasicAuth creates a function that sets the username and password for requests when passed as an options function.
func (b *Builder) BasicAuth(username, password string) *Builder {
	b.username = username
	b.password = password
	return b
}

// OAuth ...
func (b *Builder) OAuth(id, secret string) *Builder {
	//b.id = id
	//b.secret = secret
	return b
}

// builds the final Instance
func (b *Builder) Build() (*Instance, error) {
	// create an http client where the basic credentials
	// are injected automatically into requests.
	client,err := //...
	if err != nil {
		return err
	}
	return &Instance{
		client: client,
	}, nil
}

type Instance struct {
	client *http.Client
}

func(i *Instance) MyRuntimeOnlyMethod() {
	
}