in grpc-web/callout/src/main/java/com/google/apigee/callouts/util/VarResolver.java [52:60]
public <T> T getVar(String varName, Class<T> clz, T defaultValue) {
if (varName == null || varName.isEmpty()) {
return defaultValue;
}
Object varValue = msgCtx.getVariable(varName);
return tryConvert(varValue, clz, defaultValue);
}