Use serde-bytes to serialize u8 efficiently (#6442)

automerge

sdk/src/loader_instruction.rs

@@ -9,7 +9,11 @@ pub enum LoaderInstruction {
     /// * key[0] - the account to write into.
     ///
     /// The transaction must be signed by key[0]
-    Write { offset: u32, bytes: Vec<u8> },
+    Write {
+        offset: u32,
+        #[serde(with = "serde_bytes")]
+        bytes: Vec<u8>,
+    },
 
     /// Finalize an account loaded with program data for execution.
     /// The exact preparation steps is loader specific but on success the loader must set the executable
@@ -24,7 +28,10 @@ pub enum LoaderInstruction {
     /// Invoke the "main" entrypoint with the given data.
     ///
     /// * key[0] - an executable account
-    InvokeMain { data: Vec<u8> },
+    InvokeMain {
+        #[serde(with = "serde_bytes")]
+        data: Vec<u8>,
+    },
 }
 
 pub fn write(