// Strange special case: MCR, MRC.
			prog.To.Type = obj.TYPE_CONST
			x0 := p.getConstant(prog, op, &a[0])
			x1 := p.getConstant(prog, op, &a[1])
			x2 := int64(p.getRegister(prog, op, &a[2]))
			x3 := int64(p.getRegister(prog, op, &a[3]))
			x4 := int64(p.getRegister(prog, op, &a[4]))
			x5 := p.getConstant(prog, op, &a[5])
			// Cond is handled specially for this instruction.

        .set("testDate", expected)
        .build()
    assertThat(headers["testDate"]).isEqualTo("Thu, 01 Jan 1970 00:00:01 GMT")
    assertThat(headers.getDate("testDate")).isEqualTo(expected)
  }

  @Test fun setInstant() {
    val expected = Instant.ofEpochMilli(1000L)
    val headers =
      Headers
        .Builder()
        .add("Test-Instant", Instant.ofEpochMilli(0L))
        .set("Test-Instant", expected)
        .build()