class Server

Accessor for top level static properties.

Request the driver to allocate VMOs for data transfer.

Returns the allocated VMOs and their assigned IDs.

The returned VMO handle must include ZX_RIGHT_TRANSFER, ZX_RIGHT_READ and ZX_RIGHT_MAP.

If the packet stream is an output stream, then the handle must also include

ZX_RIGHT_WRITE.

Returns `ZX_ERR_INVALID_ARGS` if `min_vmo_size` is zero or `vmo_count` is zero.

Returns `ZX_ERR_NO_MEMORY` if the driver cannot allocate the requested VMOs.

Returns `ZX_ERR_BAD_STATE` if VMOs are already allocated or registered, or if the

stream is already started. Call `DeallocateVmos` or `UnregisterVmos` first to

reconfigure.

Releases all VMOs previously allocated via `AllocateVmos`.

This also occurs automatically when the `PacketStreamControl` channel is closed.

Returns `ZX_ERR_BAD_STATE` if VMOs are not currently allocated, or if the stream is

not stopped.

Registers client-allocated VMOs with the driver.

The registered VMO handle must include ZX_RIGHT_TRANSFER, ZX_RIGHT_READ and ZX_RIGHT_MAP.

If the packet stream is an input stream, then the handle must also include

ZX_RIGHT_WRITE.

Returns `ZX_ERR_INVALID_ARGS` if `vmo_infos` is empty, or if any VMO handle is invalid,

or if duplicate `vmo_id`s are found.

Returns `ZX_ERR_ACCESS_DENIED` if any VMO does not have the required rights.

Returns `ZX_ERR_BAD_STATE` if VMOs are already registered or allocated, or if the

stream is already started. Call `UnregisterVmos` or `DeallocateVmos` first to

reconfigure.

Unregisters all VMOs previously registered via `RegisterVmos`.

This also occurs automatically when the `PacketStreamControl` channel is closed.

Returns `ZX_ERR_BAD_STATE` if VMOs are not currently registered, or if the stream is

not stopped.

Connects to the data sink implemented by the driver.

This is used for audio **Output** where the driver consumes data.

Flow:

1. App writes audio data to a registered VMO.

2. App flushes the cache for the written region (if `needs_cache_flush_or_invalidate` is

true).

3. App calls `PacketStreamSink.PutPacket` with the location of the data.

4. Driver consumes the data.

If this method is called multiple times, the previous `PacketStreamSink` channel is closed,

and any pending requests on that channel are discarded. The new channel replaces the old

one.

Returns `ZX_ERR_NOT_SUPPORTED` if the stream is an input stream, or if the driver does

not support this method.

Provides a data sink to the driver.

This is used for audio **Input** where the driver produces data.

Flow:

1. Driver writes audio data to a registered VMO.

2. Driver calls `PacketStreamSink.PutPacket` with the location of the data.

3. App receives `PutPacket`.

4. App invalidates the cache for the region (if `needs_cache_flush_or_invalidate` is

true).

5. App reads the data.

If this method is called multiple times, the driver closes the previous `PacketStreamSink`

channel. The new channel replaces the old one.

Returns `ZX_ERR_NOT_SUPPORTED` if the stream is an output stream, or if the driver does

not support this method.

Start the packet-stream.

Returns `ZX_ERR_BAD_STATE` if:

* Buffers have not been allocated (if `DRIVER_OWNED` was specified)

and/or registered (if `CLIENT_OWNED` was specified). This is not applicable if

`INLINE` is supported.

* The stream is already started.

Stop the packet-stream.

Once the response is received, the stream is halted.

Behavior depends on the stream direction:

* **Output**: The driver stops consuming packets. Any pending `PacketStreamSink.PutPacket`

requests will remain pending until `Start` is called again. Clients may call

`PacketStreamSink.FlushPackets` after `Stop` to discard these pending packets.

* **Input**: The driver stops producing packets. No further `PacketStreamSink.PutPacket`

calls will be made by the driver until `Start` is called again.

Note that since `PacketStreamSink` uses a separate channel, there is no strict ordering

guarantee between `Stop` and `PacketStreamSink.PutPacket`:

* For **Output**, some in-flight `PacketStreamSink.PutPacket` calls may

complete successfully after `Stop` has returned.

* For **Input**, some in-flight `PacketStreamSink.PutPacket` calls may

arrive at the client after `Stop` has returned.

Returns `ZX_ERR_BAD_STATE` if the stream is not started.

|bind_handler| returns a handler that binds incoming connections to this

server implementation.

The returned handler borrows the server instance.

The server must outlive the provided |dispatcher|. Only after

the dispatcher is shutdown will it be safe to destroy the servers.

The server should not be moved.