Function get_buffer_memory_barrier 

pub fn get_buffer_memory_barrier<'a>(
    barrier: &BufferBarrier<'a>,
) -> (PipelineStageFlags, PipelineStageFlags, BufferMemoryBarrier<'a>)

Mapping function that translates a buffer barrier into a set of source and destination pipeline stages, and a buffer memory barrier, that can be used with Vulkan synchronization methods.