Under-workman he had employed. The Polish I used was in this manner. I had two round Copper Plates, each six Inches in Diameter, the one convex, the other concave, ground very true to one another. On the convex I ground the Object-Metal or Concave which was to be polish'd, 'till it had taken the Figure of the Convex and was ready for a Polish. Then I pitched over the convex very thinly, by dropping melted Pitch upon it, and warming it to keep the Pitch soft, whilst I ground it with the concave Copper wetted...

I used was in this manner. I had two round Copper Plates, each six
Inches in Diameter, the one convex, the other concave, ground very true
to one another. On the convex I ground the Object-Metal or Concave which
was to be polish'd, 'till it had taken the Figure of the Convex and was
ready for a Polish. Then I pitched over the convex very thinly, by
dropping melted Pitch upon it, and warming it to keep the Pitch soft,

 * </ul>
 *
 * <h3>Other notes</h3>
 *
 * <ul>
 *   <li>All ranges are shallow-immutable.
 *   <li>Instances of this type are obtained using the static factory methods in this class.
 *   <li>Ranges are <i>convex</i>: whenever two values are contained, all values in between them
 *       must also be contained. More formally, for any {@code c1 <= c2 <= c3} of type {@code C},

 * </ul>
 *
 * <h3>Other notes</h3>
 *
 * <ul>
 *   <li>All ranges are shallow-immutable.
 *   <li>Instances of this type are obtained using the static factory methods in this class.
 *   <li>Ranges are <i>convex</i>: whenever two values are contained, all values in between them
 *       must also be contained. More formally, for any {@code c1 <= c2 <= c3} of type {@code C},

	"istio.io/istio/pkg/test/framework/resource/config/cleanup"
	"istio.io/istio/pkg/test/util/yml"
)

// Context is the core context interface that is used by resources.
type Context interface {
	yml.FileWriter

	// TrackResource tracks a resource in this context. If the context is closed, then the resource will be
	// cleaned up.
	TrackResource(r Resource) ID

// this was not an explicit design goal of the context type. In fact, due to
// concurrent use it is convenient not to guarantee de-duplication.
//
// Nevertheless, in the future it could be helpful to allow users to leverage
// contexts to canonicalize instances, and it would probably be possible to
// achieve such a guarantee.

// A Context is an opaque type checking context. It may be used to share

	InstallSuffix string   `json:",omitempty"` // suffix to use in the name of the install dir
}

func newContext(c *build.Context) *Context {
	return &Context{
		GOARCH:        c.GOARCH,
		GOOS:          c.GOOS,
		GOROOT:        c.GOROOT,
		GOPATH:        c.GOPATH,
		CgoEnabled:    c.CgoEnabled,
		UseAllFiles:   c.UseAllFiles,
		Compiler:      c.Compiler,

	"istio.io/istio/pkg/config/analysis/diag"
	"istio.io/istio/pkg/config/resource"
)

// Context is a test fixture of analysis.Context
type Context struct {
	Resources []*resource.Instance
	Reports   []diag.Message
}

var _ analysis.Context = &Context{}

// Report implements analysis.Context
func (ctx *Context) Report(_ config.GroupVersionKind, t diag.Message) {
	ctx.Reports = append(ctx.Reports, t)
}

func NewContext() context.Context {
	return context.TODO()
}

// NewDefaultContext instantiates a base context object for request flows in the default namespace
func NewDefaultContext() context.Context {
	return WithNamespace(NewContext(), metav1.NamespaceDefault)
}

// WithValue returns a copy of parent in which the value associated with key is val.

	// 	var userKey key
	//
	// 	// NewContext returns a new Context that carries value u.
	// 	func NewContext(ctx context.Context, u *User) context.Context {
	// 		return context.WithValue(ctx, userKey, u)
	// 	}
	//
	// 	// FromContext returns the User value stored in ctx, if any.
	// 	func FromContext(ctx context.Context) (*User, bool) {
	// 		u, ok := ctx.Value(userKey).(*User)
	// 		return u, ok
	// 	}