consider a blob export format: "move and delete from store"

[cblgh]

hiya!

been looking over some of the SDKs and came across blob export formats. for the use case under consideration, it would be desirable to:

1. use iroh and its high level functions to sync a file (just a blob, not a document)
2. once synced, move the blob outside of the store
3. then finally, remove the blob from the store

it currently looks like the blob export api and the available configuration options (blob export formats?) keep the blob intact with the store, which is probably desirable for many use cases! but in this instance it would be important to remove it from the store after sync has been accomplished and the blob exported elsewhere.

in practice doing blobs().writeToPath (SDK method) followed by a blobs.client.delete_blob, but in one swoop of the export function call.

not sure if this additional export format is out of scope, or too complicated, but i figured i should give y'all a shout as it's stemming from a genuine use case

ty for everything!