This switches most usages of the pre-1.7 context library to use the
standard library. Remaining usages are in:
app/publisher/main.go
pkg/fs/...
Change-Id: Ia74acc39499dcb39892342a2c9a2776537cf49f1
This is round two of simplifying the BlobStreamer interface. The
continuation tokens are now sent per-item. This permits the following
item (NewMultiBlobStreamer) but also simplifies the return value (only
returns an error now) and permits the use of buffered channels as the
destination without getting out of sync.
The new NewMultiBlobStreamer is like io.MultiReader, but for
BlobStreamers, letting them be stitched together. This will be used by
the blobpacked storage layer to simplify its code, so it doesn't need
to deal with the handoff between loose and packed blobs itself. This
MultiBlobStreamer needs a 1 element buffer, which wasn't compatible
with the old BlobStreamer interface, hence the change to include the
continuation tokens with the blob on the channel.
Finally, add a new storagetest function for testing any blobstreamer
and use it for NewMultiBlobStreamer, diskpacked, and later in
blobpacked.
Updates #532
Change-Id: Iccffed289adec93ca5100c7ef8b0a8d57e05833c
Paul Lindner