in runtime/src/main/scala/org/apache/pekko/grpc/internal/ServerReflectionImpl.scala [103:113]
def containsSymbol(symbol: String, fileDesc: FileDescriptor): Boolean =
(symbol.startsWith(fileDesc.getPackage)) && // Ensure package match first
(splitNext(if (fileDesc.getPackage.isEmpty) symbol else symbol.drop(fileDesc.getPackage.length + 1)) match {
case ("", "") => false
case (typeOrService, "") =>
// fileDesc.findEnumTypeByName(typeOrService) != null || // TODO investigate if this is expected
fileDesc.findMessageTypeByName(typeOrService) != null ||
fileDesc.findServiceByName(typeOrService) != null
case (service, method) =>
Option(fileDesc.findServiceByName(service)).exists(_.findMethodByName(method) != null)
})