21/53: gnu: Add rust-futures-io-preview.

[guix-commits]

efraim pushed a commit to branch master
in repository guix.

commit c4b7a9abb654c84d815dbd927f0a6c259bd336a0
Author: Efraim Flashner <address@hidden>
Date:   Wed Aug 28 15:53:55 2019 +0300

    gnu: Add rust-futures-io-preview.
    
    * gnu/packages/crates-io.scm (rust-futures-io-preview): New variable.
---
 gnu/packages/crates-io.scm | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/gnu/packages/crates-io.scm b/gnu/packages/crates-io.scm
index c2af57e..03f2a11 100644
--- a/gnu/packages/crates-io.scm
+++ b/gnu/packages/crates-io.scm
@@ -478,6 +478,26 @@ featuring zero allocations, composability, and 
iterator-like interfaces.")
     (license (list license:asl2.0
                    license:expat))))
 
+(define-public rust-futures-io-preview
+  (package
+    (name "rust-futures-io-preview")
+    (version "0.3.0-alpha.17")
+    (source
+      (origin
+        (method url-fetch)
+        (uri (crate-uri "futures-io-preview" version))
+        (file-name (string-append name "-" version ".tar.gz"))
+        (sha256
+         (base32
+          "0fhvwhdb8ywjjbfng0ra1r8yyc9yzpyxg9sv3spb3f7w0lk40bh8"))))
+    (build-system cargo-build-system)
+    (home-page "https://rust-lang-nursery.github.io/futures-rs/";)
+    (synopsis "Async read and write traits for the futures library")
+    (description "This crate provides the @code{AsyncRead} and
+@code{AsyncWrite} traits for the @code{futures-rs} library.")
+    (license (list license:asl2.0
+                   license:expat))))
+
 (define-public rust-hex
   (package
     (name "rust-hex")