header has the current key-value store information. The first header in the snapshot stream indicates the point in time of the snapshot.
remaining_bytes is the number of blob bytes to be sent after this message
local version of server that created the snapshot. In cluster with binaries with different version, each cluster can return different result. Informs which etcd server version should be used when restoring the snapshot.
blob contains the next chunk of the snapshot in the snapshot stream.