Move static_assertion closer to where it is needed

libsignal-protocol/src/context.rs

@@ -308,14 +308,6 @@ impl Default for Context {
     }
 }
 
-// Assert that Context does not implement [`Send`] and [`Sync`] to guarantee
-// that each [`Context`] instance is only used within a single thread. This allows
-// locking to be omitted (see lock_function below).
-//
-// See https://github.com/Michael-F-Bryan/libsignal-protocol-rs/issues/49
-// for details.
-static_assertions::assert_not_impl_all!(Context: Send, Sync);
-
 /// Our Rust wrapper around the [`sys::signal_context`].
 ///
 /// # Safety
@@ -431,6 +423,13 @@ fn translate_log_level(raw: c_int) -> Level {
     }
 }
 
+// Assert that Context does not implement [`Send`] and [`Sync`] to guarantee
+// that each [`Context`] instance is only used within a single thread. 
+//
+// See https://github.com/Michael-F-Bryan/libsignal-protocol-rs/issues/49
+// for details.
+static_assertions::assert_not_impl_all!(Context: Send, Sync);
+
 unsafe extern "C" fn lock_function(_user_data: *mut c_void) {
     // Locking is not required as [`Context`] cannot be shared between
     // threads as long as it does not implement [`Sync`] and [`Send`].