Recursive depth on google.protobuf.Structs

Hi,

It seems like one of our fuzzers is failing because of a stack-overflow in protobuf's `TextFormat::Parser`. The input that libprotobuf-mutator created was a Struct that has a large recursive depth, but is not enough to trigger the max recursion limit in the parser (which is by default 2^15 - 1).
https://github.com/protocolbuffers/protobuf/blob/6fc04c3f0e07857dff1f55b884f957b4c65aea8e/src/google/protobuf/text_format.cc#L1383.

Is there some environment variable we could set to limit the recursive depth that LPM creates, or another way to handle such an input?

Thanks!