Function write_global_bitmask_block 

pub fn write_global_bitmask_block(
    out_mask: &mut Bitmask,
    block_mask: &Bitmask,
    offset: usize,
    n_lanes: usize,
)

Bulk-ORs a local bitmask block (from a SIMD mask or similar) into the global Minarrow bitmask at the correct byte offset. The block (block_mask) is expected to contain at least ceil(n_lanes/8) bytes, with the bit-packed validity bits starting from position 0.

Used to streamline repetitive boilerplate and ensure consistency across kernel null-mask handling.

Parameters

• out_mask: mutable reference to the output/global Bitmask
• block_mask: reference to the local Bitmask containing the block’s bits
• offset: starting bit offset in the global mask
• n_lanes: number of bits in this block (usually SIMD lane count)