Reduce number of lambda allocations

With the move to non-blocking invocation, interceptors now use a lot of lambdas, sometimes in the form this::method. But the JVM doesn't cache this kind of lambdas, it only caches Class::method lambdas, so we end up creating lots of extra lambda instances.

Of course, these are short-lived and are quite cheap to collect, but they can still pollute the processor cache.