rdmd takes 2-3 seconds on a first-run of a simple .d script

[BoQsc via Digitalmars-d-learn]

rdmd is a companion to the dmd compiler that simplifies the 
typical edit-compile-link-run or edit-make-run cycle to a rapid 
edit-run cycle. Like make and other tools, rdmd uses the 
relative dates of the files involved to minimize the amount of 
work necessary. Unlike make, rdmd tracks dependencies and 
freshness without requiring additional information from the 
user.

Source: https://dlang.org/rdmd.html

I have a simple standard .d script and I'm getting annoyed that 
it takes 2-3 seconds to run and see the results via rdmd.

This might sound like insanely laughable time to be annoyed by, 
but it is a enough of a problem for me to make a Thread in a D 
lang Forum.

Every time I make a change to a script it takes at least 2 
seconds on my computer for it to run, if you are beginner like me 
- you know it is not very pleasant to wait out that duration. I 
wonder if anything can be done about it, why it takes so "much" 
time, and why can't the results show up in a few milliseconds 
instead?

#!/usr/bin/env rdmd
import std.stdio, std.process;

void main() {

        writeln("This writeln is taking long time ");
        executeShell("pause");

}