src/vs/workbench/contrib/debug/common/debugModel.ts/Thread/fetchCallStack
class Thread:	async fetchCallStack(levels = 20): Promise<void> {
		if (this.stopped) {
			const start = this.callStack.length;
			const callStack = await this.getCallStackImpl(start, levels);
			this.reachedEndOfCallStack = callStack.length < levels;
			if (start < this.callStack.length) {
				// Set the stack frames for exact position we requested. To make sure no concurrent requests create duplicate stack frames #30660
				this.callStack.splice(start, this.callStack.length - start);
			}
			this.callStack = this.callStack.concat(callStack || []);
			if (typeof this.stoppedDetails?.totalFrames === 'number' && this.stoppedDetails.totalFrames === this.callStack.length) {
				this.reachedEndOfCallStack = true;
			}
		}
	}