You are tasked with designing the communication layer for a real-time chat application. First, explain in detail why the traditional request-response model of HTTP/1.x is inefficient and unsuitable for achieving real-time, bidirectional communication in such an application, considering aspects like latency, overhead, and server load. Then, compare and contrast Long Polling and WebSockets as two prominent solutions for enabling real-time, bidirectional communication between the client and server. For each solution, describe its underlying mechanism (how it works), outline its key advantages, and discuss its primary disadvantages. Conclude by identifying specific scenarios or requirements where one solution might be preferred over the other.