want    uint64
		wantErr string
	}
	tests := []testCase{
		{"x", 0, "invalid byte in chunk length"},
		{"0000000000000000", 0, ""},
		{"0000000000000001", 1, ""},
		{"ffffffffffffffff", 1<<64 - 1, ""},
		{"FFFFFFFFFFFFFFFF", 1<<64 - 1, ""},
		{"000000000000bogus", 0, "invalid byte in chunk length"},
		{"00000000000000000", 0, "http chunk length too large"}, // could accept if we wanted