proto3SingularMsgs

@get:JvmName(name = "getProto3SingularMsgs")

@set:JvmName(name = "setProto3SingularMsgs")

Force proto3 messages to have no "has_" flag.
This was default behavior until nanopb-0.4.0.

optional bool proto3_singular_msgs = 21 [default = false];