code: @Nonnull
    @ReturnsMutableCopy
    public static ICommonsOrderedSet <IProxySettings> findAllProxySettings (@Nullable final String sProtocol,
                                                                            @Nullable final String sHostName,
                                                                            @CheckForSigned final int nPort)
    {
      final ICommonsOrderedSet <IProxySettings> ret = new CommonsLinkedHashSet <> ();
      for (final IProxySettingsProvider aProvider : getAllProviders ())
        ret.addAll (aProvider.getAllProxySettings (sProtocol, sHostName, nPort));
      return ret;
    }
docs: Find all proxy settings matching the provided parameters.
  
  @param sProtocol
  Destination server protocol.
  @param sHostName
  Destination host name
  @param nPort
  Destination port
  @return A non-<code>null</code> set with all matching proxy settings. A set
  is used to avoid that the same settings are used more than once.