fixup! honor arrayDefaultMaxSize invariant

```
name \ time/op                        before         with-efficient-container  no-to-efficient-container
FromDense/bitmap-4097-10                1.45µs ± 1%               2.15µs ± 0%                1.47µs ± 2%
FromDense/run-4098-10                   1.04µs ± 4%               3.00µs ± 0%                1.04µs ± 2%
FromDense/array-4096-10                 1.45µs ± 1%               6.47µs ± 8%                5.46µs ± 1%
FromDense/bitmaps-and-runs-300000-10    3.53µs ± 0%              13.53µs ± 1%                3.57µs ± 1%

name \ speed                          before         with-efficient-container  no-to-efficient-container
FromDense/bitmap-4097-10              6.35GB/s ± 1%             4.28GB/s ± 0%              6.27GB/s ± 2%
FromDense/run-4098-10                  989MB/s ± 4%              345MB/s ± 0%               990MB/s ± 2%
FromDense/array-4096-10               6.36GB/s ± 1%             1.43GB/s ± 8%              1.69GB/s ± 1%
FromDense/bitmaps-and-runs-300000-10  15.9GB/s ± 0%              4.2GB/s ± 1%              15.8GB/s ± 1%

name \ alloc/op                       before         with-efficient-container  no-to-efficient-container
FromDense/bitmap-4097-10                8.22kB ± 0%               8.22kB ± 0%                8.22kB ± 0%
FromDense/run-4098-10                   8.22kB ± 0%               8.26kB ± 0%                8.22kB ± 0%
FromDense/array-4096-10                 8.22kB ± 0%              16.44kB ± 0%               16.41kB ± 0%
FromDense/bitmaps-and-runs-300000-10    8.35kB ± 0%               8.49kB ± 0%                8.35kB ± 0%

name \ allocs/op                      before         with-efficient-container  no-to-efficient-container
FromDense/bitmap-4097-10                  2.00 ± 0%                 2.00 ± 0%                  2.00 ± 0%
FromDense/run-4098-10                     2.00 ± 0%                 4.00 ± 0%                  2.00 ± 0%
FromDense/array-4096-10                   2.00 ± 0%                 4.00 ± 0%                  3.00 ± 0%
FromDense/bitmaps-and-runs-300000-10      6.00 ± 0%                16.00 ± 0%                  6.00 ± 0%
```

roaring.go

@@ -89,6 +89,8 @@ func (rb *Bitmap) ToDense() []uint64 {
 // FromDense creates a bitmap from a slice of uint64s representing the bitmap as a dense bitmap.
 // Useful to convert bitmaps from libraries like https://github.com/bits-and-blooms/bitset or
 // https://github.com/kelindar/bitmap into roaring bitmaps fast and with convenience.
+// This function won't create any run containers, only array and bitmap containers. It's up to
+// the caller to call RunOptimize if they want to further compress the runs of consecutive values.
 func FromDense(bitmap []uint64) *Bitmap {
 	sz := (len(bitmap) + bitmapContainerSize - 1) / bitmapContainerSize // round up
 	rb := &Bitmap{
@@ -106,6 +108,8 @@ func FromDense(bitmap []uint64) *Bitmap {
 // Useful to convert bitmaps from libraries like https://github.com/bits-and-blooms/bitset or
 // https://github.com/kelindar/bitmap into roaring bitmaps fast and with convenience.
 // Callers are responsible for ensuring that the bitmap is empty before calling this function.
+// This function won't create any run containers, only array and bitmap containers. It's up to
+// the caller to call RunOptimize if they want to further compress the runs of consecutive values.
 func (rb *Bitmap) FromDense(bitmap []uint64) {
 	if len(bitmap) == 0 {
 		return
@@ -124,10 +128,24 @@ func (rb *Bitmap) FromDense(bitmap []uint64) {
 		}
 
 		words := bitmap[:size]
-		if count := int(popcntSlice(words)); count > 0 {
-			c := &bitmapContainer{
-				bitmap:      words,
-				cardinality: count,
+		count := int(popcntSlice(words))
+
+		switch {
+		case count > arrayDefaultMaxSize:
+			c := &bitmapContainer{bitmap: words, cardinality: count}
+			rb.highlowcontainer.appendContainer(k, c, cow)
+
+		case count > 0:
+			c := &arrayContainer{content: make([]uint16, count)}
+			var pos, base int
+			for _, w := range words {
+				for w != 0 {
+					t := w & -w
+					c.content[pos] = uint16(base + int(popcount(t-1)))
+					pos++
+					w ^= t
+				}
+				base += 64
 			}
 			rb.highlowcontainer.appendContainer(k, c, cow)
 		}