optional-protocol-method.swift

protocol MyProtocol {
  func requiredMethod() -> Void
  func optionalMethod() -> Void
}

extension MyProtocol {
  func optionalMethod() -> Void {} // Default implementation
}

struct AStructThatConformsToMyProtocol:MyProtocol {
  func requiredMethod() -> Void {
    // this is mandatory
  }
}

let myInstance = AStructThatConformsToMyProtocol()