Initial QSfera import

Server/vendor/github.com/orcaman/concurrent-map/README.md

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+# concurrent map [![Build Status](https://travis-ci.com/orcaman/concurrent-map.svg?branch=master)](https://travis-ci.com/orcaman/concurrent-map)
+
+As explained [here](http://golang.org/doc/faq#atomic_maps) and [here](http://blog.golang.org/go-maps-in-action), the `map` type in Go doesn't support concurrent reads and writes. `concurrent-map` provides a high-performance solution to this by sharding the map with minimal time spent waiting for locks.
+
+Prior to Go 1.9, there was no concurrent map implementation in the stdlib. In Go 1.9, `sync.Map` was introduced. The new `sync.Map` has a few key differences from this map. The stdlib `sync.Map` is designed for append-only scenarios. So if you want to use the map for something more like in-memory db, you might benefit from using our version. You can read more about it in the golang repo, for example [here](https://github.com/golang/go/issues/21035) and [here](https://stackoverflow.com/questions/11063473/map-with-concurrent-access)
+
+## usage
+
+Import the package:
+
+```go
+import (
+	"github.com/orcaman/concurrent-map"
+)
+
+```
+
+```bash
+go get "github.com/orcaman/concurrent-map"
+```
+
+The package is now imported under the "cmap" namespace.
+
+## example
+
+```go
+
+	// Create a new map.
+	m := cmap.New()
+
+	// Sets item within map, sets "bar" under key "foo"
+	m.Set("foo", "bar")
+
+	// Retrieve item from map.
+	if tmp, ok := m.Get("foo"); ok {
+		bar := tmp.(string)
+	}
+
+	// Removes item under key "foo"
+	m.Remove("foo")
+
+```
+
+For more examples have a look at concurrent_map_test.go.
+
+Running tests:
+
+```bash
+go test "github.com/orcaman/concurrent-map"
+```
+
+## guidelines for contributing
+
+Contributions are highly welcome. In order for a contribution to be merged, please follow these guidelines:
+- Open an issue and describe what you are after (fixing a bug, adding an enhancement, etc.).
+- According to the core team's feedback on the above mentioned issue, submit a pull request, describing the changes and linking to the issue.
+- New code must have test coverage.
+- If the code is about performance issues, you must include benchmarks in the process (either in the issue or in the PR).
+- In general, we would like to keep `concurrent-map` as simple as possible and as similar to the native `map`. Please keep this in mind when opening issues.
+
+## language
+- [中文说明](./README-zh.md)
+
+## license
+MIT (see [LICENSE](https://github.com/orcaman/concurrent-map/blob/master/LICENSE) file)