val relay = edit(file, upstream, metadata, 5)
    val source1 = relay.newSource()!!.buffer()
    val source2 = relay.newSource()!!.buffer()
    assertThat(source1.readUtf8(5)).isEqualTo("abcde")
    assertThat(source2.readUtf8(5)).isEqualTo("abcde")
    assertThat(source2.readUtf8(5)).isEqualTo("fghij")
    assertThat(source1.readUtf8(5)).isEqualTo("fghij")
    assertThat(source1.exhausted()).isTrue()

    assertEquals("", Strings.commonPrefix("abc", ""));
    assertEquals("", Strings.commonPrefix("", "abc"));
    assertEquals("", Strings.commonPrefix("abcde", "xyz"));
    assertEquals("", Strings.commonPrefix("xyz", "abcde"));
    assertEquals("", Strings.commonPrefix("xyz", "abcxyz"));
    assertEquals("a", Strings.commonPrefix("abc", "aaaaa"));
    assertEquals("aa", Strings.commonPrefix("aa", "aaaaa"));

    assertEquals("", Strings.commonPrefix("abc", ""));
    assertEquals("", Strings.commonPrefix("", "abc"));
    assertEquals("", Strings.commonPrefix("abcde", "xyz"));
    assertEquals("", Strings.commonPrefix("xyz", "abcde"));
    assertEquals("", Strings.commonPrefix("xyz", "abcxyz"));
    assertEquals("a", Strings.commonPrefix("abc", "aaaaa"));
    assertEquals("aa", Strings.commonPrefix("aa", "aaaaa"));

			testRemaining{0, 0},
		},
	}, {
		maker: makeSparse{makeReg{5, "abcde"}, sparseHoles{{2, 3}}, 8},
		tests: []testFnc{
			testRemaining{8, 5},
			testWrite{"ab\x00\x00\x00cde", 8, nil},
			testWrite{"a", 0, ErrWriteTooLong},
			testRemaining{0, 0},
		},
	}, {
		maker: makeSparse{makeReg{5, "abcde"}, sparseHoles{{2, 3}}, 8},
		tests: []testFnc{

    protocol: Protocol,
    mockWebServer: MockWebServer,
  ) {
    setUp(protocol, mockWebServer)
    server.enqueue(MockResponse(body = "ABCDE"))
    val call = client.newCall(Request(server.url("/foo")))
    val response = call.execute()
    assertThat(response.body.string()).isEqualTo("ABCDE")
    assertThat(response.code).isEqualTo(200)
    assertThat(response.message).isEqualTo("")
    assertThat(response.protocol).isEqualTo(protocol)

			testRead{0, "", io.EOF},
		},
	}, {
		maker: makeSparse{makeReg{"abcde", 5}, sparseDatas{{0, 2}, {5, 3}}, 8},
		tests: []testFnc{
			testRemaining{8, 5},
			testRead{3, "ab\x00", nil},
			testRead{10, "\x00\x00cde", io.EOF},
			testRemaining{0, 0},
		},
	}, {
		maker: makeSparse{makeReg{"abcde", 5}, sparseDatas{{0, 2}, {5, 3}}, 8},
		tests: []testFnc{
			testRemaining{8, 5},

	// Output: "64 bytes or fewer"
}

func ExampleBuffer_Len() {
	var b bytes.Buffer
	b.Grow(64)
	b.Write([]byte("abcde"))
	fmt.Printf("%d", b.Len())
	// Output: 5
}

func ExampleBuffer_Next() {
	var b bytes.Buffer
	b.Grow(64)
	b.Write([]byte("abcde"))
	fmt.Printf("%s\n", b.Next(2))
	fmt.Printf("%s\n", b.Next(2))
	fmt.Printf("%s", b.Next(2))
	// Output:
	// ab
	// cd
	// e
}

			keys:     []string{"etag", "md5"},
			want:     map[string]string{"content-type": "application/octet-stream", "x-amz-storage-class": "STANDARD"},
		},
		{
			name:     "2",
			metadata: map[string]string{"content-type": "application/octet-stream", "etag": "de75a98baf2c6aef435b57dd0fc33c86", "x-amz-storage-class": "REDUCED_REDUNDANCY", "md5sum": "abcde"},
			keys:     []string{"etag", "md5sum"},

		{"DATA", "·D(SB)/5,$0.0", "bad float size for DATA argument: 5"},
		{"DATA", "·E(SB)/4,$·A(SB)", "bad addr size for DATA argument: 4"},
		{"DATA", "·F(SB)/8,$·A(SB)", ""},
		{"DATA", "·G(SB)/5,$\"abcde\"", ""},
		{"GLOBL", "", "expect two or three operands for GLOBL"},
		{"GLOBL", "0,1", "GLOBL symbol \"<erroneous symbol>\" must be a symbol(SB)"},
		{"GLOBL", "@B(SB), 0", "expected '(', found B"}, // Issue 23580.

  public void testReadEmptyString() throws IOException {
    assertReadsCorrectly("");
  }

  public void testReadsStringsCorrectly() throws IOException {
    assertReadsCorrectly("abc");
    assertReadsCorrectly("abcde");
    assertReadsCorrectly("abcdefghijkl");
    assertReadsCorrectly(
        ""
            + "abcdefghijklmnopqrstuvwxyz\n"
            + "ABCDEFGHIJKLMNOPQRSTUVWXYZ\r"
            + "0123456789\r\n"