│   │   └── io/
│   │       ├── ContentCache.java       # In-memory or file-based caching
│   │       └── ContentOutputStream.java # Threshold-based output stream
│   └── test/java/org/codelibs/curl/
│       ├── CurlTest.java          # Factory method tests
│       ├── CurlRequestTest.java   # Request builder tests
│       ├── CurlResponseTest.java  # Response handling tests
│       ├── CurlExceptionTest.java # Exception tests
│       └── io/