@Override
  public boolean supports(String attribute) {
    // any attribute name is supported
    return true;
  }
Attribute provider that provides the {@link UserDefinedFileAttributeView} ("user"). Unlike most
other attribute providers, this one has no pre-defined set of attributes. Rather, it allows
arbitrary user defined attributes to be set (as {@code ByteBuffer} or {@code byte[]}) and read
(as {@code byte[]}).

@author Colin Decker
jimfs/src/main/java/com/google/common/jimfs/UserDefinedAttributeProvider.java