Renamed FLUSH to FLUSH_ALL_DATA to avoid c++ enum collision with Synchronization::FLUSH

* `code = NOT_AUTHORIZED` The identity doesn't have permission to delete this value, in this case `status.statusMessage` will be "permission denied."

### Flus

The `FLUSH` operation flushes any outstanding PUTs or DELETEs on the device. For example, if the client `PUT` many keys with `synchronization=WRITEBACK` the data

would not be guaranteed to be persisted, so power cycling could result in lost data. When a `FLUSH` command returns, all previous operations with `synchronization=WRITEBACK` on

### Flush

The `FLUSH_ALL_DATA` operation flushes any outstanding PUTs or DELETEs on the device. For example, if the client `PUT` many keys with `synchronization=WRITEBACK` the data

would not be guaranteed to be persisted, so power cycling could result in lost data. When a `FLUSH_ALL_DATA` command returns, all previous operations with `synchronization=WRITEBACK` on

this connection are guaranteed to be persisted. Data on separate connections is not guaranteed to be persisted, but may as an indirect consequence of this operation.

**Request Message**

    identity: ...

    connectionID: ...

    sequence: ...

    // messageType should be FLUSH

    messageType: FLUSH

    // messageType should be FLUSH_ALL_DATA

    messageType: FLUSH_ALL_DATA

  }

  body {

  }

  header {

    ackSequence: ...

    // messageType should be FLUSH_RESPONSE

    messageType: FLUSH_RESPONSE

    // messageType should be FLUSH_ALL_DATA_RESPONSE

    messageType: FLUSH_ALL_DATA_RESPONSE

  }

  body {

  }

  status {

  // A successful FLUSH will return SUCCESS

  // A successful FLUSH_ALL_DATA will return SUCCESS

    code: SUCCESS

  }

}

```

**Permissions**

Having unrestricted `WRITE` or `DELETE` permissions is sufficient to execute a `FLUSH` command.

Having unrestricted `WRITE` or `DELETE` permissions is sufficient to execute a `FLUSH_ALL_DATA` command.

## Read Operations

    NOOP = 30;

    NOOP_RESPONSE = 29;

    FLUSH = 32;

    FLUSH_RESPONSE = 31;

    FLUSH_ALL_DATA = 32;

    FLUSH_ALL_DATA_RESPONSE = 31;

  }

}