TUN-3201: Create base cloudflared UI structure

vendor/github.com/rivo/tview/primitive.go

@@ -0,0 +1,57 @@
+package tview
+
+import "github.com/gdamore/tcell"
+
+// Primitive is the top-most interface for all graphical primitives.
+type Primitive interface {
+	// Draw draws this primitive onto the screen. Implementers can call the
+	// screen's ShowCursor() function but should only do so when they have focus.
+	// (They will need to keep track of this themselves.)
+	Draw(screen tcell.Screen)
+
+	// GetRect returns the current position of the primitive, x, y, width, and
+	// height.
+	GetRect() (int, int, int, int)
+
+	// SetRect sets a new position of the primitive.
+	SetRect(x, y, width, height int)
+
+	// InputHandler returns a handler which receives key events when it has focus.
+	// It is called by the Application class.
+	//
+	// A value of nil may also be returned, in which case this primitive cannot
+	// receive focus and will not process any key events.
+	//
+	// The handler will receive the key event and a function that allows it to
+	// set the focus to a different primitive, so that future key events are sent
+	// to that primitive.
+	//
+	// The Application's Draw() function will be called automatically after the
+	// handler returns.
+	//
+	// The Box class provides functionality to intercept keyboard input. If you
+	// subclass from Box, it is recommended that you wrap your handler using
+	// Box.WrapInputHandler() so you inherit that functionality.
+	InputHandler() func(event *tcell.EventKey, setFocus func(p Primitive))
+
+	// Focus is called by the application when the primitive receives focus.
+	// Implementers may call delegate() to pass the focus on to another primitive.
+	Focus(delegate func(p Primitive))
+
+	// Blur is called by the application when the primitive loses focus.
+	Blur()
+
+	// GetFocusable returns the item's Focusable.
+	GetFocusable() Focusable
+
+	// MouseHandler returns a handler which receives mouse events.
+	// It is called by the Application class.
+	//
+	// A value of nil may also be returned to stop the downward propagation of
+	// mouse events.
+	//
+	// The Box class provides functionality to intercept mouse events. If you
+	// subclass from Box, it is recommended that you wrap your handler using
+	// Box.WrapMouseHandler() so you inherit that functionality.
+	MouseHandler() func(action MouseAction, event *tcell.EventMouse, setFocus func(p Primitive)) (consumed bool, capture Primitive)
+}