Decode a Docker multiplexed stream into the given output IO. Each frame: [stream_type(1), padding(3), size(4 big-endian)] followed by payload.
Parse a Docker image reference into repository and tag. Examples: "alpine" => {"alpine", "latest"} "alpine:3.18" => {"alpine", "3.18"} "my/repo:v1.0" => {"my/repo", "v1.0"}