private com.google.protobuf.SingleFieldBuilderV3<
              com.google.devtools.cloudtrace.v2.TruncatableString,
              com.google.devtools.cloudtrace.v2.TruncatableString.Builder,
              com.google.devtools.cloudtrace.v2.TruncatableStringOrBuilder>
          getOriginalFunctionNameFieldBuilder() {
        if (originalFunctionNameBuilder_ == null) {
          originalFunctionNameBuilder_ =
              new com.google.protobuf.SingleFieldBuilderV3<
                  com.google.devtools.cloudtrace.v2.TruncatableString,
                  com.google.devtools.cloudtrace.v2.TruncatableString.Builder,
                  com.google.devtools.cloudtrace.v2.TruncatableStringOrBuilder>(
                  getOriginalFunctionName(), getParentForChildren(), isClean());
          originalFunctionName_ = null;
        }
        return originalFunctionNameBuilder_;
      }
<pre>
An un-mangled function name, if `function_name` is mangled.
To get information about name mangling, run
[this search](https://www.google.com/search?q=cxx+name+mangling).
The name can be fully-qualified (up to 1024 bytes).
</pre>

<code>.google.devtools.cloudtrace.v2.TruncatableString original_function_name = 2;</code>
java-trace/proto-google-cloud-trace-v2/src/main/java/com/google/devtools/cloudtrace/v2/StackTrace.java