private void invokeOnComplete() {
        try (SafeCloseable ignored = ctx.push()) {
            if (listener != null) {
                listener.onComplete();
            }
        } catch (Throwable t) {
            // This should not be possible with normal generated stubs which do not implement
            // onComplete, but is conceivable for a completely manually constructed stub.
            logger.warn("Error in gRPC onComplete handler.", t);
        }
    }
Cancels a call when the call was closed by a client, not by server.
grpc/src/main/java/com/linecorp/armeria/internal/server/grpc/AbstractServerCall.java