code: @Nullable
    public static String getAllBytesAsString (@Nullable final IHasInputStream aISP,
                                              @Nonnull @Nonempty final Charset aCharset)
    {
      if (aISP == null)
        return null;
  
      return getAllBytesAsString (aISP.getInputStream (), aCharset);
    }
docs: Read all bytes from the passed input stream into a string.
  
  @param aISP
  The input stream provider to read from. May be <code>null</code> .
  @param aCharset
  The charset to use. May not be <code>null</code> .
  @return The String or <code>null</code> if the parameter or the resolved
  input stream is <code>null</code>.