change: TransportV2Ext::invoke(…,features,…) can take key-value pai…

…rs more flexibly.

Value can now also be owned, which is useful if the value type is a
`Cow<'_, String>`.

git-transport/src/client/blocking_io/traits.rs

@@ -70,7 +70,7 @@ pub trait TransportV2Ext {
     fn invoke<'a>(
         &mut self,
         command: &str,
-        capabilities: impl Iterator<Item = (&'a str, Option<&'a str>)>,
+        capabilities: impl Iterator<Item = (&'a str, Option<impl AsRef<str>>)>,
         arguments: Option<impl Iterator<Item = bstr::BString>>,
     ) -> Result<Box<dyn ExtendedBufRead + Unpin + '_>, Error>;
 }
@@ -79,14 +79,14 @@ impl<T: Transport> TransportV2Ext for T {
     fn invoke<'a>(
         &mut self,
         command: &str,
-        capabilities: impl Iterator<Item = (&'a str, Option<&'a str>)>,
+        capabilities: impl Iterator<Item = (&'a str, Option<impl AsRef<str>>)>,
         arguments: Option<impl Iterator<Item = BString>>,
     ) -> Result<Box<dyn ExtendedBufRead + Unpin + '_>, Error> {
         let mut writer = self.request(WriteMode::OneLfTerminatedLinePerWriteCall, MessageKind::Flush)?;
         writer.write_all(format!("command={}", command).as_bytes())?;
         for (name, value) in capabilities {
             match value {
-                Some(value) => writer.write_all(format!("{}={}", name, value).as_bytes()),
+                Some(value) => writer.write_all(format!("{}={}", name, value.as_ref()).as_bytes()),
                 None => writer.write_all(name.as_bytes()),
             }?;
         }