Add .bytes() fn to BlockId (#1157)

Author: juliusl

sdk/storage_blobs/src/options/block_id.rs

@@ -1,13 +1,26 @@
 use azure_core::AppendToUrlQuery;
 use bytes::Bytes;
 
+/// Struct wrapping the bytes of a block blob block-id,
+///
+/// A block id cannot exceed 64 bytes before encoding. In addition all block id's in a block list must be the same length.
+/// Reference: https://learn.microsoft.com/en-us/rest/api/storageservices/put-block#uri-parameters
+///
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct BlockId(Bytes);
 
 impl BlockId {
+    /// Returns a new block id,
+    ///
     pub fn new(block_id: impl Into<Bytes>) -> Self {
         Self(block_id.into())
     }
+
+    /// Returns clone of bytes,
+    ///
+    pub fn bytes(&self) -> Bytes {
+        self.0.clone()
+    }
 }
 
 impl AppendToUrlQuery for BlockId {