My project is using protobuf ^1.0.0 which is higher than your version. When I rollback to ^0.13.4, tons of error happened in proto generated dart file. I have checked the release message of dart protobuf and the 1.0.0 is released in the same month with 0.13, so I think you should update the protobuf version.
My project is using protobuf ^1.0.0 which is higher than your version. When I rollback to ^0.13.4, tons of error happened in proto generated dart file. I have checked the release message of dart protobuf and the 1.0.0 is released in the same month with 0.13, so I think you should update the protobuf version.