Normal breakpoints don't get hit util exception line gets hit.

I downloaded the repo,and launched the code without changing any lines,and the workspace stops at the top line ("# VS Code Mock Debug") normally,and I set the a breakpoint at line 3,then continue,but the execution doesn't stop at line 3.
I dive into the code,and see the possible reasons to cause this:
In MockRuntime class,there's a method called findNextStatement:

 */
	 private findNextStatement(reverse: boolean, stepEvent?: string): boolean {

		for (let ln = this.currentLine; reverse ? ln >= 0 : ln < this.sourceLines.length; reverse ? ln-- : ln++) {

			// is there a source breakpoint?
			const breakpoints = this.breakPoints.get(this._sourceFile);
			if (breakpoints) {
				const bps = breakpoints.filter(bp => bp.line === ln);
                        ...
                        }
                   ...
              }
       }

The breakpoints will be undefined,cuz this.breakpoints holds an entry, the key of which is "c:/Code Repository/vscode-mock-debug/sampleWorkspace/readme.md",
but the _sourceFile is "C:/Code Repository/vscode-mock-debug/sampleWorkspace/readme.md" now,see what's different?
the previous one starts with a lowercase drive volume while another starts with a uppercase one,and please note that I have a space char in my workspace path.
Platform:Windows
VSCodeVersion:1.76.2

Start in the MockRuntime.findNextStatement method and reproduce the breakpoint behavior on Windows with a workspace path containing a space. Inspect how the breakpoint map key and _sourceFile path are produced and compared; done means a normal breakpoint at line 3 is hit without requiring the exception line.