[SPDK] Blob store

Hi, Is there any example code for blob store to use nvme device directly without the block dev layer?  If not, is there even a document on the order in which APIs need to be invoked to set this up correctly?  The way I have it setup, spdk_bs_init () followed by spdk_bs_md_create_blob () both succeed, but spdk_bs_md_open_blob () spins forever.  It keeps issuing reads to lba=3. Thanks