fixup! Add support for transferring compressed blobs via ByteStream

clarify the read_offset/write_offset meaning for compressed-blobs

build/bazel/remote/execution/v2/remote_execution.proto

@@ -217,6 +217,9 @@ service ActionCache {
 // * `optional_metadata` is implementation specific data, which clients MAY omit.
 //   Servers MAY ignore this metadata.
 //
+// Note that when writing compressed blobs, the `WriteRequest.write_offset`
+// refers to the offset in the uncompressed form of the blob.
+//
 // Data can alternatively be uploaded in compressed form, with the following
 // `WriteRequest.resource_name` form:
 // `{instance_name}/uploads/{uuid}/compressed-blobs/{compressor}/{uncompressed_hash}/{uncompressed_size}{/optional_metadata}`
@@ -271,6 +274,9 @@ service ActionCache {
 //   the case of failure such as retrying a limited number of times or
 //   surfacing an error to the user.
 //
+// Note that when reading compressed blobs, the `ReadRequest.read_offset`
+// refers to the offset in the uncompressed form of the blob.
+//
 // Servers MAY use any compression level they choose, including different
 // levels for different blobs (e.g. choosing a level designed for maximum
 // speed for data known to be incompressible).