`<xiosbase>`: `std::ios_base::sync_with_stdio` has no effect in VS

Describe the bug

std::ios_base::sync_with_stdio has no effect in the STL but cout becomes much faster after calling sync_with_stdio on mingw + libstdc++ .

#include <cstdio>
#include <ctime>
#include <iostream>
using namespace std;
int main() {
    ios::sync_with_stdio(false);

    clock_t start, end;
    start = clock();

    for (int i = 0; i < 1e+4; i++) {
        cout << i;
    }

    end = clock();
    cout << endl;
    cout << end - start << endl;
    return 0;
}

Expected behavior

sync_with_stdio should give some performance.

STL version

Microsoft Visual Studio Community 2022
Version 17.6.0 Preview 3.0

Additional context

Devcom-10347093

I suggested to the user to add setvbuf(stdout, nullptr, _IOLBF, 16384); after sync_with_stdio but this optimization is still missing.

Start by compiling and running the provided sample with Microsoft Visual Studio 17.6 Preview 3.0, then compare its timing with the reported mingw + libstdc++ behavior. Investigate the MSVC STL implementation of std::ios_base::sync_with_stdio and verify that the change produces a measurable performance effect without breaking stream behavior.