Create variable of type Map[string]interface{} in gRPC protoc buffer golang

proto3 has type Any

import "google/protobuf/any.proto";

message ErrorStatus {
  string message = 1;
  repeated google.protobuf.Any details = 2;
}

but if you look at its implementation, it is simply as

message Any {
  string type_url = 1;
  bytes value = 2;
}

You have to define such a message yourself by possibly using reflection and an intermediate type.

See example application

https://github.com/golang/protobuf/issues/60