Performance Mystery: Is Go's Startup Speed Slow

Replit's Universal Package Manager (UPM) suffered from a performance issue where even very simple tasks took about 200ms. Since this tool, written in Go, was running slower than expected, the developer began to question the startup speed of Go itself.

After measuring execution time inside the code, it turned out the actual logic was very fast, taking only around 1-5ms. This meant that most of the time was already being spent during the loading phase, before the program even reached its first line of code.

A simple Hello World program ran in just 11ms, confirming that the issue wasn't with Go itself. Based on this, the developer started narrowing down the cause using the Bug Sandwich technique, which involves finding the difference between a normal case and a problematic case.