C# Safe Base64 Helper with c# 8

Base64Helper.cs

public static class Base64Helper
{
  /// <summary>
  /// Convert to url safe base 64
  /// </summary>
  /// <param name="base64">base64 string</param>
  /// <returns></returns>
  public static string ToSafeBase64(string base64)
  {
    return base64
      .TrimEnd('=')
      .Replace('+', '-')
      .Replace('/', '_');
  }

  /// <summary>
  /// Reverse origin base 64 from url safe base 64
  /// </summary>
  /// <param name="safe64">url safe base 64</param>
  /// <returns></returns>
  public static string FromSafeBase64(string safe64)
  {
    return safe64
      .Replace('-', '+')
      .Replace('_', '/')
      +
      (safe64.Length % 4) switch
      {
        2 => "==",
        3 => "="
      };
  }
}