block: Enable request submission in batch when using io_uring

Implement the batch submission function for raw disk, default it is
enabled. After parsing the requests this method is
called for better IO latency and bandwidth.

Signed-off-by: Bo Chen <bchen@crusoe.ai>
Signed-off-by: Muminul Islam <muislam@microsoft.com>

block/src/async_io.rs

@@ -79,6 +79,9 @@ pub enum AsyncIoError {
     /// Failed synchronizing file.
     #[error("Failed synchronizing file")]
     Fsync(#[source] std::io::Error),
+    /// Failed submitting batch requests.
+    #[error("Failed submitting batch requests: {0}")]
+    SubmitBatchRequests(#[source] std::io::Error),
 }
 
 pub type AsyncIoResult<T> = std::result::Result<T, AsyncIoError>;