class WireWeakSyncClientImpl

Asks the server to transfer focus to the View specified by `view_ref`,

with the authority of the requestor ViewRef. Such a request may be

honored or denied.

If the request was honored, and it triggers a focus change, a FocusEvent

(with focused=true) is issued to the newly-focused View, and a

FocusEvent (with focused=false) is issued to the previous View.

The result callback indicates that the request was received and honored.

It does not guarantee that the requested View actually received a

FocusEvent in time.

The request may be denied for many reasons, for example:

- if `view_ref` is invalid

- if there is no View backed by `view_ref`

- if there is no requestor ViewRef accessible to Focuser

- if the requestor ViewRef lacks authority over `view_ref`'s View

- if `view_ref`'s View is not hittable or may not receive focus

etc. A denied request is indicated with a Error.

Allocates 56 bytes of message buffer on the stack. No heap allocation necessary.

Sets the auto focus target to the View specified by `view_ref`.

To unset the target, pass in an empty table.

If a target has been set, then whenever the caller's View would receive

focus, an attempt is made to transfer focus immediately to the target

instead. If the target is unfocusable, the new target is the first

focusable ancestor of the target instead. Setting an auto focus target

places no limitations on simultaneous use of RequestFocus().

An auto focus target is "valid" only while it is a descendant of the

caller's View in the ViewTree. Specifying an invalid auto focus target is

allowed, since it may become valid later.

It is the client's responsibility to ensure the target is a valid

receiver of auto focus.

If the target is invalid when the auto focus behavior would trigger, then

the attempt to move focus will silently fail and focus will remain with

the caller's View.

A target may become invalid and then become valid again any number of

times; auto focus will continue to function whenever the target is

in a valid state, and will continue to ignore the target while it's in an

invalid state.

If the focus would by some further automatic mechanism return to the

caller's View (e.g. if the target is unfocusable), then focus will

remain with the caller's View.

AutoFocusError is currently never returned, and is reserved for possible

future use.

Allocates 72 bytes of message buffer on the stack. No heap allocation necessary.