* products that you would get from nesting for loops:
   *
   * <pre>{@code
   * for (B b0 : lists.get(0)) {
   *   for (B b1 : lists.get(1)) {
   *     ...
   *     ImmutableList<B> tuple = ImmutableList.of(b0, b1, ...);
   *     // operate on tuple
   *   }
   * }
   * }</pre>
   *

func TestWriterReadFromCounts(t *testing.T) {
	var w0 writeCountingDiscard
	b0 := NewWriterSize(&w0, 1234)
	b0.WriteString(strings.Repeat("x", 1000))
	if w0 != 0 {
		t.Fatalf("write 1000 'x's: got %d writes, want 0", w0)
	}
	b0.WriteString(strings.Repeat("x", 200))
	if w0 != 0 {
		t.Fatalf("write 1200 'x's: got %d writes, want 0", w0)
	}
	io.Copy(b0, onlyReader{strings.NewReader(strings.Repeat("x", 30))})
	if w0 != 0 {

   * products that you would get from nesting for loops:
   *
   * <pre>{@code
   * for (B b0 : sets.get(0)) {
   *   for (B b1 : sets.get(1)) {
   *     ...
   *     ImmutableList<B> tuple = ImmutableList.of(b0, b1, ...);
   *     // operate on tuple
   *   }
   * }
   * }</pre>
   *

}

func (sw *sparseFileWriter) Write(b []byte) (n int, err error) {
	overwrite := int64(len(b)) > sw.logicalRemaining()
	if overwrite {
		b = b[:sw.logicalRemaining()]
	}

	b0 := b
	endPos := sw.pos + int64(len(b))
	for endPos > sw.pos && err == nil {
		var nf int // Bytes written in fragment
		dataStart, dataEnd := sw.sp[0].Offset, sw.sp[0].endOffset()

						}
						all, err := io.ReadAll(r)
						if err != nil {
							return err
						}
						foundData[name] = all
					}
				}
			} else {
				b0 := ""
				if ndjson {
					b, _ := json.Marshal(file)
					b0 = fmt.Sprintf("%s: ", string(b))
				}
				b, err := decode(r, file)
				if err != nil {
					return err
				}
				b = bytes.TrimSpace(b)
				if !ndjson {

00000a0 8b fc 9c ca cc 08 cc cb cc 5e d2 1c 88 d9 7e bb
00000b0 4f bb 3a 3f 75 f1 5d 7f 8f c2 68 67 77 8f 25 ff
00000c0 84 e2 93 2d ef a4 95 3d 71 4e 2c b9 b0 87 c3 be
00000d0 3d f8 a7 60 24 61 c5 ef ae 9e c8 6c 6d 4e 69 c8
00000e0 67 65 34 f8 37 76 2d 76 5c 54 f3 95 65 49 c7 0f
00000f0 18 71 4b 7e 5b 6a d1 79 47 61 41 b0 4e 2a 74 45
0000100 43 58 12 b2 5a a5 c6 7d 68 55 88 d4 98 75 18 6d
0000110 08 d1 1f 8f 5a 9e 96 ee 45 cf a4 84 4e 4b e8 50

	A2 = struct{ a, b int }
	A3 = int
	A4 = func(A3, float64) *A0
	A5 = func(x int, _ float64) *[]string
)

type (
	B0 A0
	B1 []string
	B2 struct{ a, b int }
	B3 struct{ a, c int }
	B4 func(int, float64) *B0
	B5 func(x int, y float64) *A1
)

type	C0 = B0
</pre>

<p>
these types are identical:
</p>

<pre>
A0, A1, and []string
A2 and struct{ a, b int }

	A1 = A0
	A2 = struct{ a, b int }
	A3 = int
	A4 = func(A3, float64) *A0
	A5 = func(x int, _ float64) *[]string

	B0 A0
	B1 []string
	B2 struct{ a, b int }
	B3 struct{ a, c int }
	B4 func(int, float64) *B0
	B5 func(x int, y float64) *A1

	C0 = B0
	D0[P1, P2 any] struct{ x P1; y P2 }
	E0 = D0[int, string]
)
</pre>

<p>
these types are identical:
</p>