问如何在Swift中向使用Combine发出的HTTP GET请求添加正文？

EN

import Foundation
import Combine
//MARK: - Object to retrieve from JSON
struct Doctor: Codable, Identifiable {
    let id = UUID()
    let patients: [Patients]
}
struct Patients: Codable, Identifiable {
    let id: String
    let name: String
    let phone: String
    enum CodingKeys: String, CodingKey {
        case id = "_id"
        case name
        case phone
    }
}
class Network {
  enum Error: LocalizedError {
    case invalidResponse
    case addressUnreachable(URL)
    var errorDescription: String? {
      switch self {
      case .invalidResponse:
        return "The server responded with garbage."
      case .addressUnreachable(let url):
        return "\(url.absoluteString) is unreachable."
      }
    }
  }
  let urlRequest = URL(string: URL)!
  let networkQueue = DispatchQueue(label: "Networking",
                                   qos: .default,
                                   attributes: .concurrent)
  func downloadPatients() -> AnyPublisher<Doctor, Error> {
    URLSession.shared
      .dataTaskPublisher(for: urlRequest)
      .receive(on: networkQueue)
      .map(\.data)
      .decode(type: Doctor.self, decoder: JSONDecoder())
      .mapError { (error) -> Network.Error in
        switch error {
        case is URLError:
          return Error.addressUnreachable(self.urlRequest)
        default:
          return Error.invalidResponse
        }
    }
    .eraseToAnyPublisher()
  }
}
let networkRequest = Network()
 func loadPatients() {
       cancelable = networkRequest.downloadPatients()
            .sink(
                receiveCompletion: {
                receiveValue: { doctor in
                    self.localPatients = doctor.patients
                    self.isShowing = false
            }
        )
    }