class SynchronizedDispatcher

Creates a dispatcher for performing asynchronous operations.

|options| provides the dispatcher configuration. This will panic if options does not

set FDF_DISPATCHER_OPTION_SYNCHRONIZED.

|name| is reported via diagnostics. It is similar to setting the name of a thread. Names longer

than `ZX_MAX_NAME_LEN` may be truncated.

|scheduler_role| is a hint. It may or not impact the priority the work scheduler against the

dispatcher is handled at. It may or may not impact the ability for other drivers to share

zircon threads with the dispatcher.

|shutdown_handler| will be called after |ShutdownAsync| has been called, and the dispatcher

has completed its asynchronous shutdown. The client must keep any pointers that are

referenced in |shutdown_handler| alive until the handler runs.

# Thread requirements

This must be called from a thread managed by the driver runtime.

# Errors

ZX_ERR_NOT_SUPPORTED: |options| is not a supported configuration, which is any of the

following:

* `FDF_DISPATCHER_OPTION_UNSYNCHRONIZED` with `FDF_DISPATCHER_OPTION_ALLOW_SYNC_CALLS`.

ZX_ERR_INVALID_ARGS: This was not called from a thread managed by the driver runtime.

ZX_ERR_NO_RESOURCES: A thread needed to be spawned to create this dispatcher, but couldn't be.

This is likely because a dispatcher that allows sync calls was requested, but the thread pool

is currently at its limit.

ZX_ERR_BAD_STATE: Dispatchers are currently not allowed to be created, such as when a driver

is being shutdown by its driver host.