It provides a synchronous gRPC server that implements MongoDB gRPC Protocol and delegates threading to the gRPC core library. It wraps every incoming gRPC stream into an instance of IngressSession. The server provides the per-operation threading model, where threads allocated by the gRPC core library are used to receive, process, and respond to individual operations. A new configuration option settable at startup, will set an upper-bound on the number of threads allocated by the gRPC core library (similar to maxIncomingConnections for MongoRPC).