Use trace tool

Use the GODEBUG environment variable or //go:debug directives to control specific runtime behaviors and opt out of breaking changes in newer Go versions. Set the environment variable before running your program to apply settings globally, or add directives to your source files for fine-grained control.

export GODEBUG=panicnil=1,http2client=0
go run main.go

Alternatively, add directives to the top of your Go source file:

//go:debug panicnil=1
//go:debug http2client=0
package main

func main() {
    // Your code here
}

GODEBUG acts like a set of switches that let you tell the Go runtime to behave like an older version or disable specific new features. You use it when a recent Go update breaks your existing code, allowing you to keep working without rewriting everything. Think of it as a compatibility mode that lets you toggle specific behaviors on or off.