gnu: Add rust-loop9-0.1.

* gnu/packages/crates-io.scm (rust-loop9-0.1): New variable.

gnu/packages/crates-io.scm

@@ -21585,6 +21585,29 @@ (define-public rust-loom-0.1
         ("rust-serde-derive" ,rust-serde-derive-1)
         ("rust-serde-json" ,rust-serde-json-1))))))
 
+(define-public rust-loop9-0.1
+  (package
+    (name "rust-loop9")
+    (version "0.1.3")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (crate-uri "loop9" version))
+       (file-name (string-append name "-" version ".tar.gz"))
+       (sha256
+        (base32 "0h4rys8001cdq4l2f30k66wmvscm4lb2laxgpia794p5652800x7"))))
+    (build-system cargo-build-system)
+    (arguments
+     `(#:skip-build? #t
+       #:cargo-inputs
+       (("rust-imgref" ,rust-imgref-1))))
+    (home-page "https://lib.rs/loop9")
+    (synopsis "Helper function to visit every pixel and its neighbors")
+    (description
+     "This package provides a tiny helper function to visit every pixel in the
+image together with its neighboring pixels.")
+    (license license:expat)))
+
 (define-public rust-lopdf-0.25
   (package
     (name "rust-lopdf")