Fixes,

error: unused import: `crate::base64`
  --> /home/build/workspace/smithy-rs/aws/sdk/build/aws-sdk/sdk/aws-smithy-types/src/blob.rs:11:5
   |
11 | use crate::base64;
   |     ^^^^^^^^^^^^^
   |
   = note: `-D unused-imports` implied by `-D warnings`

Author: thomas-k-cameron

rust-runtime/aws-smithy-types/src/blob.rs

@@ -7,9 +7,8 @@
 use serde::Serialize;
 #[cfg(all(aws_sdk_unstable, feature = "serde-deserialize"))]
 use serde::{de::Visitor, Deserialize};
-
+#[cfg(all(aws_sdk_unstable, any(feature = "serde-deserialize", feature = "serde-serialize")))]
 use crate::base64;
-
 /// Binary Blob Type
 ///
 /// Blobs represent protocol-agnostic binary content.