syntax = "proto3";
package metadata;
// Metadata is the metadata of the message
message Metadata {
// PreviousVertex is the name of the previous vertex
string previous_vertex = 1;
// SystemMetadata is the system metadata of the message
// Key of the map is the group name
map<string, KeyValueGroup> sys_metadata = 2;
// UserMetadata is the user metadata of the message
// Key of the map is the group name
map<string, KeyValueGroup> user_metadata = 3;
}
// KeyValueGroup is a group of key-value pairs for a given group.
message KeyValueGroup {
map<string, bytes> key_value = 1;
}