var fw fileWriter
		switch maker := v.maker.(type) {
		case makeReg:
			fw = &regFileWriter{w, maker.size}
			wantStr = maker.wantStr
		case makeSparse:
			if !validateSparseEntries(maker.sph, maker.size) {
				t.Fatalf("invalid sparse map: %v", maker.sph)
			}
			spd := invertSparseEntries(maker.sph, maker.size)
			fw = &regFileWriter{w, maker.makeReg.size}
			fw = &sparseFileWriter{fw, spd, 0}

		var fr fileReader
		switch maker := v.maker.(type) {
		case makeReg:
			r := testNonEmptyReader{strings.NewReader(maker.str)}
			fr = &regFileReader{r, maker.size}
		case makeSparse:
			if !validateSparseEntries(maker.spd, maker.size) {
				t.Fatalf("invalid sparse map: %v", maker.spd)
			}
			sph := invertSparseEntries(maker.spd, maker.size)
			r := testNonEmptyReader{strings.NewReader(maker.makeReg.str)}

    Original Software, to make, have made, use, practice, sell, and
    offer for sale, and/or otherwise dispose of the Original Software
    (or portions thereof).

    (c) The licenses granted in Sections 2.1(a) and (b) are effective on
    the date Initial Developer first distributes or otherwise makes the
    Original Software available to a third party under the terms of this
    License.

        } else {
          continue; // delete this entry; we already copied an earlier one for the same key
        }
      }
      newEntries[out++] = entry;
    }
    return newEntries;
  }

  /** Makes an entry usable internally by a new ImmutableMap without rereading its contents. */
  static <K, V> ImmutableMapEntry<K, V> makeImmutable(Entry<K, V> entry, K key, V value) {
    boolean reusable =

4. Submit a pull request

          MyAnalyticsTag(...)
        }

        return chain.proceed(chain.request())
      }
    ```

 *  New: Support request bodies on HTTP/1.1 connection upgrades.
 *  New: `EventListener.plus()` makes it easier to observe events in multiple listeners.
 *  Fix: Don't spam logs with _‘Method isLoggable in android.util.Log not mocked.’_ when using
    OkHttp in Robolectric and Paparazzi tests.

        assertTrue(h.isValid());

        // Tree id change makes it invalid
        when(tree.getTreeId()).thenReturn(11L);
        assertFalse(h.isValid());

        // Connected=false makes it invalid
        when(tree.getTreeId()).thenReturn(10L);
        when(tree.isConnected()).thenReturn(false);
        assertFalse(h.isValid());

        // Mark closed makes it invalid
        when(tree.isConnected()).thenReturn(true);

		ttl:       ttl,
		size:      size,
		evictList: NewList[K, V](),
		items:     make(map[K]*Entry[K, V]),
		onEvict:   onEvict,
		done:      make(chan struct{}),
	}

	// initialize the buckets
	res.buckets = make([]bucket[K, V], numBuckets)
	for i := 0; i < numBuckets; i++ {
		res.buckets[i] = bucket[K, V]{entries: make(map[K]*Entry[K, V])}
	}

* There should be tests testing the source example.
* Before the PR is applied, the new tests should fail.
* After applying the PR, the new tests should pass.
* Coverage should stay at 100%.
* If you see the PR makes sense, or we discussed it and considered it should be accepted, you can add commits on top of the PR to tweak it, to add docs, tests, format, refactor, remove extra files, etc.

	return err
}

// NewTierConfigMgr - creates new tier configuration manager,
func NewTierConfigMgr() *TierConfigMgr {
	return &TierConfigMgr{
		drivercache: make(map[string]WarmBackend),
		Tiers:       make(map[string]madmin.TierConfig),
	}
}

func (config *TierConfigMgr) refreshTierConfig(ctx context.Context, objAPI ObjectLayer) {
	const tierCfgRefresh = 15 * time.Minute