An introduction to marble diagrams for visual representation

It is difficult to visualize Rx Streams, as the data flows asynchronously. The designers of Rx systems have created a set of visualization cues called marble diagrams: Let us write a small program and depict logic of the map Operator as a marble diagram.

//------------------ Map.cpp 
#include "rxcpp/rx.hpp" 
#include "rxcpp/rx-test.hpp" 
#include <ioStream> 
#include <array> 
int main() { 
    auto ints = rxcpp::observable<>::range(1,10). 
                 map( [] ( int n  ) {return n*n; }); 
    ints.subscribe( 
            [](int v){printf("OnNext: %dn", v);}, 
            [](){printf("OnCompletedn");}); 
} 

Rather than giving a description of marble diagrams, let's look at a marble diagram that depicts the map operator:

The top part of the marble diagram shows a timeline where a series of values (represented as circles) are displayed. Each of the value will be passing through a map Operator, which takes a lambda...