Add Reuse function to uv::Tcp (#1208)

This allows reusing the Tcp object in cases when the connection errors out.

wpiutil/src/main/native/include/wpi/uv/Tcp.h

@@ -56,6 +56,18 @@ class Tcp final : public NetworkStreamImpl<Tcp, uv_tcp_t> {
     return Create(*loop, flags);
   }
 
+  /**
+   * Reuse this handle.  This closes the handle, and after the close completes,
+   * reinitializes it (identically to Create) and calls the provided callback.
+   * Unlike Close(), it does NOT emit the closed signal, however, IsClosing()
+   * will return true until the callback is called.  This does nothing if
+   * IsClosing() is true (e.g. if Close() was called).
+   *
+   * @param flags Flags
+   * @param callback Callback
+   */
+  void Reuse(std::function<void()> callback, unsigned int flags = AF_UNSPEC);
+
   /**
    * Accept incoming connection.
    *
@@ -304,6 +316,12 @@ class Tcp final : public NetworkStreamImpl<Tcp, uv_tcp_t> {
 
  private:
   Tcp* DoAccept() override;
+
+  struct ReuseData {
+    std::function<void()> callback;
+    unsigned int flags;
+  };
+  std::unique_ptr<ReuseData> m_reuseData;
 };
 
 /**