https://RustRocket.rs -- Cloud Monk Losang Jinpa, Ph.D., MCSE / MCT, https://Rustaceans.rs, Full Stack Cloud Native Rust DevOps Engineer - Rocket Framework Rust Microservices on Kubernetes-AWS-Azure-GCP

“call operator - a nonstatic member function having the name operator() and taking zero or more arguments; see also callable object. Lambdas (574)” (EMCppSfe 2021)