How do you implement prompt caching in the Claude API?

Caching Code Example

{
  "model": "claude-3-5-sonnet-20241022",
  "max_tokens": 1024,
  "messages": [
    {
      "role": "user",
      "content": [
        {
          "type": "text",
          "text": "...very long resource document here...",
          "cache_control": {"type": "ephemeral"}
        },
        {
          "type": "text",
          "text": "Analyze the document above."
        }
      ]
    }
  ]
}