* a directory
 */
    public static final int ATTR_DIRECTORY  = 0x10;
/**
 * A file with this bit on as returned by <tt>getAttributes()</tt> or set
 * with <tt>setAttributes()</tt> is an archived file
 */
    public static final int ATTR_ARCHIVE    = 0x20;

    // extended file attribute encoding(others same as above)
    static final int ATTR_COMPRESSED       = 0x800;

    assertFailsWith<IllegalArgumentException> {
      Request.Builder().addHeader("a b", "c")
    }.also { expected ->
      assertThat(expected.message).isEqualTo("Unexpected char 0x20 at 1 in header name: a b")
    }
  }

  @Test
  fun requestHeaderNameWithTabForbidden() {
    assertFailsWith<IllegalArgumentException> {
      Request.Builder().addHeader("a\tb", "c")

UTF-8-encoded bytes may represent a single integer value.  For
instance, the literal <code>'a'</code> holds a single byte representing
a literal <code>a</code>, Unicode U+0061, value <code>0x61</code>, while
<code>'ä'</code> holds two bytes (<code>0xc3</code> <code>0xa4</code>) representing
a literal <code>a</code>-dieresis, U+00E4, value <code>0xe4</code>.
</p>

<p>