| 123456789101112131415161718 | syntax = "proto3";import "nanopb.proto";message SubMsg{    int32 field = 1;}message Message1{    int32 proto3_default = 1;    int32 proto3_off = 2 [(nanopb).proto3 = false];    int32 proto3_on = 3 [(nanopb).proto3 = true];    SubMsg normal_submsg = 4;    SubMsg sng_submsg = 5 [(nanopb).proto3_singular_msgs = true];}
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