writeByteNTimes

pub fn writeByteNTimes(self: Self, byte: u8, n: usize) anyerror!void {
    var bytes: [256]u8 = undefined;
    @memset(bytes[0..], byte);

    var remaining: usize = n;
    while (remaining > 0) {
        const to_write = @min(remaining, bytes.len);
        try self.writeAll(bytes[0..to_write]);
        remaining -= to_write;
    }
}