mediasoup-demo-v3中添加flexfec需要Consumer.hpp如何修改

要在mediasoup-demo-v3中添加flexfec，需要对Consumer.hpp文件进行以下修改：

1. 在文件开头添加以下头文件：

#include "mediasoup/FlexfecReceiver.hpp"

2. 在Consumer class中添加以下成员变量：

// Flexfec receiver instance.
mediasoup::FlexfecReceiver* flexfecReceiver{nullptr};

3. 在Consumer class的构造函数中，初始化flexfecReceiver：

// Initialize flexfec receiver.
flexfecReceiver = new mediasoup::FlexfecReceiver();

4. 在Consumer class的析构函数中释放flexfecReceiver：

// Release flexfec receiver.
if (flexfecReceiver != nullptr)
{
  delete flexfecReceiver;
  flexfecReceiver = nullptr;
}

5. 在Consumer class中添加以下方法，用于处理flexfec：

void Consumer::HandleFlexfec(const webrtc::RtpPacketReceived& packet)
{
  // Pass the packet to the flexfec receiver.
  flexfecReceiver->ReceivePacket(packet);
}

void Consumer::GetFlexfecPackets(std::vector<webrtc::RtpPacketReceived>& packets)
{
  // Get the list of flexfec packets from the receiver.
  flexfecReceiver->GetAndResetPackets(packets);
}

这些修改应该能够让Consumer class支持flexfec。请注意：这些修改可能需要与mediasoup的版本和实际需求相适应。