Function cmd_pipeline_barrier 

pub unsafe fn cmd_pipeline_barrier(
    command_buffer: VkCommandBuffer,
    src_stage_mask: VkPipelineStageFlags,
    dst_stage_mask: VkPipelineStageFlags,
    dependency_flags: VkDependencyFlags,
    memory_barrier_count: u32,
    memory_barriers: *const VkMemoryBarrier,
    buffer_memory_barrier_count: u32,
    buffer_memory_barriers: *const VkBufferMemoryBarrier,
    image_memory_barrier_count: u32,
    image_memory_barriers: *const VkImageMemoryBarrier,
)

Safety

direct calling ffi functions.