Some requests will have a cached response. When this cached response isn’t fresh, OkHttp can do a _conditional GET_ to download an updated response if it’s newer than what’s cached. This requires headers like `If-Modified-Since` and `If-None-Match` to be added.

## Rewriting Responses

    should not use them for communication between trusted and untrusted code.

6.  For the mainline flavor, we test the libraries using OpenJDK 8, 11, and 17
    on Linux, with some additional testing on newer JDKs and on Windows. Some
    features, especially in `com.google.common.io`, may not work correctly in
    non-Linux environments. For the Android flavor, our unit tests also run on
    API level 21 (Lollipop).

![put](https://raw.githubusercontent.com/minio/minio/master/docs/bucket/versioning/versioning_PUT_versionEnabled.png)

 * as a single request/response exchange.
 *
 * ## Modern TLS
 *
 * There are trade-offs when selecting which options to include when negotiating a secure connection
 * to a remote host. Newer TLS options are quite useful:
 *
 *  * Server Name Indication (SNI) enables one IP address to negotiate secure connections for
 *    multiple domain names.
 *

      if (existing != null) {
        return existing;
      }
      L created = supplier.get();
      ArrayReference<L> newRef = new ArrayReference<>(created, index, queue);
      while (!locks.compareAndSet(index, existingRef, newRef)) {
        // we raced, we need to re-read and try again
        existingRef = locks.get(index);
        existing = existingRef == null ? null : existingRef.get();

	#   sessionToken: SESSION-TOKEN # Available when rotating credentials are used

  # optional flags based filtering criteria
  # for all source objects
  flags:
	filter:
	  newerThan: "7d" # match objects newer than this value (e.g. 7d10h31s)
	  olderThan: "7d" # match objects older than this value (e.g. 7d10h31s)
	  createdAfter: "date" # match objects created after "date"
	  createdBefore: "date" # match objects created before "date"

R8 / ProGuard
-------------

R8 and ProGuard are both code optimizers for `.class` files.

R8 is the [default optimizer][r8] in Android Studio 3.4 and newer. It works well with all
releases of OkHttp.

ProGuard was the previous default. We’re [tracking problems][proguard_problems] with interactions

                    Version.V20,
                    "modelVersion",
                    null,
                    "of '" + string + "' is newer than the versions supported by this version of Maven: "
                            + validVersions + ". Building this project requires a newer version of Maven.",
                    tracker);

        } else if (olderThanAll) {

            }
        }
    ]
}
```

This JSON rule is equivalent to the following MinIO Client command:
```
mc ilm rule add --noncurrent-expire-days 30 --noncurrent-expire-newer 5 myminio/mydata
```

#### 3.2.a Automatic removal of noncurrent versions keeping only most recent ones immediately (MinIO only extension)

	Distribution []int `json:"distribution"`
	// Checksums holds all bitrot checksums of all erasure encoded blocks
	Checksums []ChecksumInfo `json:"checksum,omitempty"`
}

// Equal equates current erasure info with newer erasure info.
// returns false if one of the following check fails
// - erasure algorithm is different
// - data blocks are different
// - parity blocks are different
// - block size is different