class RingBufferProperties

Returns whether no field is set.

When set to true, indicates that the ring buffer runs in a different cache coherency domain,

and thus clients must ensure that their data writes are flushed all the way to main memory

(during playback), or that their view of the ring buffer must be invalidated before any

reads (during capture). This is because there may be hardware external to the CPUs that

reads/writes main memory, bypassing the CPUs.

When set to false, indicates that the ring buffer runs in the same cache coherency domain as

the CPUs, hence the driver is not required to flush/invalidate the ring buffer.

Note that in this case, the driver and client still must synchronize their data access, for

instance by inserting the appropriate acquire fences before reading and releasing fences

after writing, or (more commonly) by obeying the Producer/Consumer pattern described in

[Ring Buffer Behavior](https://fuchsia.dev/fuchsia-src/development/audio/ring_buffer.md).

Required.

When set to true, indicates that the ring buffer runs in a different cache coherency domain,

and thus clients must ensure that their data writes are flushed all the way to main memory

(during playback), or that their view of the ring buffer must be invalidated before any

reads (during capture). This is because there may be hardware external to the CPUs that

reads/writes main memory, bypassing the CPUs.

When set to false, indicates that the ring buffer runs in the same cache coherency domain as

the CPUs, hence the driver is not required to flush/invalidate the ring buffer.

Note that in this case, the driver and client still must synchronize their data access, for

instance by inserting the appropriate acquire fences before reading and releasing fences

after writing, or (more commonly) by obeying the Producer/Consumer pattern described in

[Ring Buffer Behavior](https://fuchsia.dev/fuchsia-src/development/audio/ring_buffer.md).

Required.

The driver's best estimate of the time needed for the hardware to emit (during playback) or

accept (during capture) frames, after a channel is activated by `SetActiveChannels`.

The driver estimates that after `SetActiveChannels(channel)->(set_time)` enables a channel,

its data will resume flowing at approximately `set_time` + `turn_on_delay`.

Hardware can take time to become fully operational (e.g. due to a power state change, or

communication delays between a Bluetooth driver's multiple hardware entities). The client

must take this delay into account, if it is unacceptable to drop the actual audio frames

and instead play/capture silence during this interval.

If not included, `turn_on_delay` is unknown.

Optional.

The driver's best estimate of the time needed for the hardware to emit (during playback) or

accept (during capture) frames, after a channel is activated by `SetActiveChannels`.

The driver estimates that after `SetActiveChannels(channel)->(set_time)` enables a channel,

its data will resume flowing at approximately `set_time` + `turn_on_delay`.

Hardware can take time to become fully operational (e.g. due to a power state change, or

communication delays between a Bluetooth driver's multiple hardware entities). The client

must take this delay into account, if it is unacceptable to drop the actual audio frames

and instead play/capture silence during this interval.

If not included, `turn_on_delay` is unknown.

Optional.

Size (in bytes) of the temporary buffers or FIFOs used by the driver when consuming or

generating the ring buffer contents.

The `driver_transfer_bytes` field is covered extensively in

[Ring Buffer Behavior](https://fuchsia.dev/fuchsia-src/development/audio/ring_buffer.md).

`driver_transfer_bytes` must not include the impact of delays caused by hardware or software

processing abstracted by the driver. Those delays are communicated by `internal_delay` and

`external_delay` fields in `DelayInfo`; they are orthogonal to this value.

Required.

Size (in bytes) of the temporary buffers or FIFOs used by the driver when consuming or

generating the ring buffer contents.

The `driver_transfer_bytes` field is covered extensively in

[Ring Buffer Behavior](https://fuchsia.dev/fuchsia-src/development/audio/ring_buffer.md).

`driver_transfer_bytes` must not include the impact of delays caused by hardware or software

processing abstracted by the driver. Those delays are communicated by `internal_delay` and

`external_delay` fields in `DelayInfo`; they are orthogonal to this value.

Required.