class Duplicate

Create an additional [`fuchsia.sysmem2/BufferCollectionToken`] from this

one, referring to the same buffer collection.

The created token is a child of this token in the

[`fuchsia.sysmem2/Node`] heirarchy.

This method can be used to add a participant, by transferring the newly

created token to another participant.

This one-way message can be used instead of the two-way

[`fuchsia.sysmem2/BufferCollectionToken.DuplicateSync`] FIDL call in

performance sensitive cases where it would be undesireable to wait for

sysmem to respond to

[`fuchsia.sysmem2/BufferCollectionToken.DuplicateSync`] or when the

client code isn't structured to make it easy to duplicate all the needed

tokens at once.

After sending one or more `Duplicate` messages, and before sending the

newly created child tokens to other participants (or to other

[`fuchsia.sysmem2/Allocator`] channels), the client must send a

[`fuchsia.sysmem2/Node.Sync`] and wait for the `Sync` response. The

`Sync` call can be made on the token, or on the `BufferCollection`

obtained by passing this token to `BindSharedCollection`. Either will

ensure that the server knows about the tokens created via `Duplicate`

before the other participant sends the token to the server via separate

`Allocator` channel.

All tokens must be turned in via

[`fuchsia.sysmem2/Allocator.BindSharedCollection`] or

[`fuchsia.sysmem2/Node.Release`] for a `BufferCollection` to

successfully allocate buffers.

All table fields are currently required.

+ request `rights_attenuation_mask` The rights bits that are zero in

this mask will be absent in the buffer VMO rights obtainable via the

client end of `token_request`. This allows an initiator or

intermediary participant to attenuate the rights available to a

delegate participant. This does not allow a participant to gain rights

that the participant doesn't already have. The value

`ZX_RIGHT_SAME_RIGHTS` can be used to specify that no attenuation

should be applied.

+ These values for rights_attenuation_mask result in no attenuation:

+ `ZX_RIGHT_SAME_RIGHTS` (preferred)

+ 0xFFFFFFFF (this is reasonable when an attenuation mask is

computed)

+ 0 (deprecated - do not use 0 - an ERROR will go to the log)

+ request `token_request` is the server end of a `BufferCollectionToken`

channel. The client end of this channel acts as another participant in

the shared buffer collection.