class OpenForVerifiedRead

Requests that the device verify that the provided `config` matches the

one on disk, and that the given `seal` covers the content of the

superblock. If all match as expected, then the device will bind a child

device named `verified` which speaks the `fuchsia.hardware.block`

protocol and enter the `verified-read` mode. Reads issued to the

`verified` block device will either successfully return the same content

as the `mutable` block device would have returned at the time the volume

was authored, or return a failure. That is to say: modifying the

underlying storage will cause the `verified` device to return read

failures for any modified blocks as `ZX_ERR_IO_DATA_INTEGRITY` rather

than data other than what was present at the time `CloseAndGenerateSeal`

was called.

* Returns `ZX_ERR_BAD_STATE` if the device was not in the `closed`

state at the time of the call

* Returns `ZX_ERR_INVALID_ARGS` if `config` lacks either `hash_function` or `block_size`

* Returns `ZX_ERR_INVALID_ARGS` if `seal` is of an unrecognized variant

* Returns `ZX_ERR_IO_DATA_INTEGRITY` if the `seal` provided is inconsistent with

the superblock, or if the properties in `config` are inconsistent with the

configuration data stored in the superblock on the underlying block device.

* Returns the underlying I/O error code if the underlying block device

returns an error.

On success, the device binds a child device `verified`, enters

`verified-read` mode, and returns from this call.