formatUtf16Le

fn formatUtf16Le(utf16le: []const u16, writer: *std.Io.Writer) std.Io.Writer.Error!void {
    var buf: [300]u8 = undefined; // just an arbitrary size
    var it = Utf16LeIterator.init(utf16le);
    var u8len: usize = 0;
    while (it.nextCodepoint() catch replacement_character) |codepoint| {
        u8len += utf8Encode(codepoint, buf[u8len..]) catch
            utf8Encode(replacement_character, buf[u8len..]) catch unreachable;
        // make sure there's always enough room for another maximum length UTF-8 codepoint
        if (u8len + 4 > buf.len) {
            try writer.writeAll(buf[0..u8len]);
            u8len = 0;
        }
    }
    try writer.writeAll(buf[0..u8len]);
}