make trait non-generic, and Send safe

src/async_trait.rs

@@ -6,7 +6,8 @@ use async_trait::async_trait;
 /// The `R` type is your resource repository (a database for instance) that will be passed to the
 /// [`find`](Resolver::find) and [`endpoint`](Resolver::endpoint) functions.
 #[async_trait]
-pub trait Resolver<R> {
+pub trait Resolver {
+    type Repo: Send;
     /// Returns the domain name of the current instance.
     async fn instance_domain<'a>(&self) -> &'a str;
 
@@ -20,14 +21,14 @@ pub trait Resolver<R> {
         &self,
         prefix: Prefix,
         acct: String,
-        resource_repo: R,
+        resource_repo: Self::Repo,
     ) -> Result<Webfinger, ResolverError>;
 
     /// Returns a WebFinger result for a requested resource.
     async fn endpoint(
         &self,
-        resource: impl Into<String>,
-        resource_repo: R,
+        resource: impl Into<String> + Send,
+        resource_repo: Self::Repo,
     ) -> Result<Webfinger, ResolverError> {
         let resource = resource.into();
         let mut parsed_query = resource.splitn(2, ':');