In the builder base class I see this api
https://github.com/apache/arrow/blob/ad1697e5d25eeaff5630421f55b0120f45cf0ce1/cpp/src/arrow/array/builder_base.h#L149
// Vector append. Treat each zero byte as a nullzero. If valid_bytes is
null
// assume all of length bits are valid.
void UnsafeAppendToBitmap(const uint8_t* valid_bytes, int64_t length)
Is valid_bytes an allocation of size (int8_t) * length, using an entire
byte to indicate validity for each element in the array or is this a null
bitmask where in each byte in valid_bytes encodes 8 values, one per bit?
If this is using a byte per value is there an approved way of using a
builder to initialize an array using the memory layout described here
https://arrow.apache.org/docs/memory_layout.html#null-bitmaps?
