fixup: Remove dead code in KJ async.

c++/src/kj/async-io-unix.c++

@@ -549,71 +549,6 @@ private:
       }
     }
   }
-
-  template <typename T>
-  kj::Promise<kj::Maybe<T>> tryReceiveFdImpl() {
-    struct msghdr msg;
-    memset(&msg, 0, sizeof(msg));
-
-    struct iovec iov;
-    memset(&iov, 0, sizeof(iov));
-    char c;
-    iov.iov_base = &c;
-    iov.iov_len = 1;
-    msg.msg_iov = &iov;
-    msg.msg_iovlen = 1;
-
-    // Allocate space to receive a cmsg.
-    union {
-      struct cmsghdr cmsg;
-      char cmsgSpace[CMSG_SPACE(sizeof(int))];
-    };
-    msg.msg_control = &cmsg;
-    msg.msg_controllen = sizeof(cmsgSpace);
-
-#ifdef MSG_CMSG_CLOEXEC
-    int recvmsgFlags = MSG_CMSG_CLOEXEC;
-#else
-    int recvmsgFlags = 0;
-#endif
-
-    ssize_t n;
-    KJ_NONBLOCKING_SYSCALL(n = recvmsg(fd, &msg, recvmsgFlags));
-    if (n < 0) {
-      return observer.whenBecomesReadable().then([this]() {
-        return tryReceiveFdImpl<T>();
-      });
-    } else if (n == 0) {
-      return kj::Maybe<T>(nullptr);
-    } else {
-      KJ_REQUIRE(msg.msg_controllen >= sizeof(cmsg),
-          "expected to receive FD over socket; received data instead");
-
-      // We expect an SCM_RIGHTS message with a single FD.
-      KJ_REQUIRE(cmsg.cmsg_level == SOL_SOCKET);
-      KJ_REQUIRE(cmsg.cmsg_type == SCM_RIGHTS);
-      KJ_REQUIRE(cmsg.cmsg_len == CMSG_LEN(sizeof(int)));
-
-      int receivedFd;
-      memcpy(&receivedFd, CMSG_DATA(&cmsg), sizeof(receivedFd));
-      return kj::Maybe<T>(wrapFd(receivedFd, (T*)nullptr));
-    }
-  }
-
-  AutoCloseFd wrapFd(int newFd, AutoCloseFd*) {
-    auto result = AutoCloseFd(newFd);
-#ifndef MSG_CMSG_CLOEXEC
-    setCloseOnExec(result);
-#endif
-    return result;
-  }
-  Own<AsyncCapabilityStream> wrapFd(int newFd, Own<AsyncCapabilityStream>*) {
-    return kj::heap<AsyncStreamFd>(eventPort, newFd,
-#ifdef MSG_CMSG_CLOEXEC
-        LowLevelAsyncIoProvider::ALREADY_CLOEXEC |
-#endif
-        LowLevelAsyncIoProvider::TAKE_OWNERSHIP);
-  }
 };
 
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