Implement Send for RpcServerConnection

Test: N/A
Bug: 382291660
Change-Id: I0e5fbede384c67439d54c7b8f53ae8622886f704

Author: Hasini Gunasinghe

libs/binder/rust/rpcbinder/src/server/trusty.rs

@@ -106,6 +106,10 @@ pub struct RpcServerConnection {
     ctx: *mut c_void,
 }
 
+// SAFETY: The opaque handle: `ctx` points into a dynamic allocation,
+// and not tied to anything specific to the current thread.
+unsafe impl Send for RpcServerConnection {}
+
 impl Drop for RpcServerConnection {
     fn drop(&mut self) {
         // We do not need to close handle_fd since we do not own it.