process: add raw_arg method to Command (#5704)

tokio/src/process/mod.rs

@@ -400,6 +400,22 @@ impl Command {
         self
     }
 
+    /// Append literal text to the command line without any quoting or escaping.
+    ///
+    /// This is useful for passing arguments to `cmd.exe /c`, which doesn't follow
+    /// `CommandLineToArgvW` escaping rules.
+    ///
+    /// **Note**: This is an [unstable API][unstable] but will be stabilised once
+    /// tokio's MSRV is sufficiently new. See [the documentation on
+    /// unstable features][unstable] for details about using unstable features.
+    #[cfg(windows)]
+    #[cfg(tokio_unstable)]
+    #[cfg_attr(docsrs, doc(cfg(all(windows, tokio_unstable))))]
+    pub fn raw_arg<S: AsRef<OsStr>>(&mut self, text_to_append_as_is: S) -> &mut Command {
+        self.std.raw_arg(text_to_append_as_is);
+        self
+    }
+
     /// Inserts or updates an environment variable mapping.
     ///
     /// Note that environment variable names are case-insensitive (but case-preserving) on Windows,