diff --git a/vendor/github.com/boljen/go-bitmap/atomic.go b/vendor/github.com/boljen/go-bitmap/atomic.go
new file mode 100644
index 0000000..f04d76e
--- /dev/null
+++ b/vendor/github.com/boljen/go-bitmap/atomic.go
@@ -0,0 +1,64 @@
+package bitmap
+
+import (
+	"sync/atomic"
+	"unsafe"
+)
+
+var oobPanic = "SetAtomic not allowed on a bitmapSlice of cap() < 4"
+
+// SetAtomic is similar to Set except that it performs the operation atomically.
+func SetAtomic(bitmap []byte, targetBit int, targetValue bool) {
+	ov := (*[1]uint32)(unsafe.Pointer(&bitmap[targetBit/32]))[:]
+	SetAtomicUint32(ov, targetBit%32, targetValue)
+}
+
+// SetAtomic is similar to Set except that it performs the operation atomically.
+// It needs a bitmapSlice where the capacity is at least 4 bytes.
+func _SetAtomic(bitmapSlice []byte, targetBit int, targetValue bool) {
+	targetByteIndex := targetBit / 8
+	targetBitIndex := targetBit % 8
+	targetOffset := 0
+
+	// SetAtomic needs to modify 4 bytes of data so we panic when the slice
+	// doesn't have a capacity of at least 4 bytes.
+	if cap(bitmapSlice) < 4 {
+		panic(oobPanic)
+	}
+
+	// Calculate the Offset of the targetByte inside the 4-byte atomic batch.
+	// This is needed to ensure that atomic operations can happen as long as
+	// the bitmapSlice equals 4 bytes or more.
+	if cap(bitmapSlice) < targetByteIndex+3 {
+		targetOffset = cap(bitmapSlice) - targetByteIndex
+	}
+
+	// This gets a pointer to the memory of 4 bytes inside the bitmapSlice.
+	// It stores this pointer as an *uint32 so that it can be used to
+	// execute sync.atomic operations.
+	targetBytePointer := (*uint32)(unsafe.Pointer(&bitmapSlice[targetByteIndex-targetOffset]))
+
+	for {
+		// localValue is a copy of the uint32 value at *targetBytePointer.
+		// It's used to check whether the targetBit must be updated,
+		// and if so, to construct the new value for targetBytePointer.
+		localValue := atomic.LoadUint32(targetBytePointer)
+
+		// This "neutralizes" the uint32 conversion by getting a pointer to the
+		// 4-byte array stored undereneath the uint32.
+		targetByteCopyPointer := (*[4]byte)(unsafe.Pointer(&localValue))
+
+		// Work is done when targetBit is already set to targetValue.
+		if GetBit(targetByteCopyPointer[targetOffset], targetBitIndex) == targetValue {
+			return
+		}
+
+		// Modify the targetBit and update memory so that the targetBit is the only bit
+		// that has been modified in the batch.
+		referenceValue := localValue
+		SetBitRef(&targetByteCopyPointer[targetOffset], targetBitIndex, targetValue)
+		if atomic.CompareAndSwapUint32(targetBytePointer, referenceValue, localValue) {
+			break
+		}
+	}
+}