Events
======

Events allow you to capture metrics on your application’s HTTP calls. Use events to monitor:

 * The size and frequency of the HTTP calls your application makes. If you’re making too many calls, or your calls are too large, you should know about it!
 * The performance of these calls on the underlying network. If the network’s performance isn’t sufficient, you need to either improve the network or use less of it.

### EventListener

}

type concreteF[RCT RC[RG], RG any] struct {
	makeFn func() Fn /* ERROR "not enough type arguments for type Fn: have 1, want 2" */ [RCT]
}

func (c *concreteF[RCT, RG]) Fn() Fn /* ERROR "not enough type arguments for type Fn: have 1, want 2" */ [RCT] {
	return c.makeFn()
}

// creating complex traces that are mostly or completely correct.
func (t *Trace) Generation(gen uint64) *Generation {
	g := &Generation{
		trace:   t,
		gen:     gen,
		strings: make(map[string]uint64),
		stacks:  make(map[stack]uint64),
	}
	t.gens = append(t.gens, g)
	return g
}

// Generate creates a test file for the trace.
func (t *Trace) Generate() []byte {
	// Trace file contents.

		// so make sure at least these modules are found. See issue 46254. If this list
		// becomes a nuisance to update, can be replaced with len(goroot.modules) check.
		knownGOROOTModules := [...]string{
			"std",
			"cmd",
			// The "misc" module sometimes exists, but cmd/distpack intentionally removes it.
		}
		var seen = make(map[string]bool) // Key is module path.

				alloc: []BitRange{{bits + 2, PallocChunkPages - (bits + 2)}},
				min:   1,
				max:   3, // Make it so that max would have us try to break the huge page.
				want:  BitRange{0, bits + 2},
			}
			if 3*bits < PallocChunkPages {
				// We need at least 3 huge pages in a chunk for this test to make sense.
				tests["PreserveHugePageMiddle"] = test{

	}
	if dir == "" {
		return "", false, fmt.Errorf("missing user-config dir")
	}
	return filepath.Join(dir, "go/env"), false, nil
}

func initEnvCache() {
	envCache.m = make(map[string]string)
	envCache.goroot = make(map[string]string)
	if file, _, _ := EnvFile(); file != "" {
		readEnvFile(file, "user")
	}
	goroot := findGOROOT(envCache.m["GOROOT"])
	if goroot != "" {

	// use the overridden concurrent streams setting or make the default of 250 explicit so we can size MaxUploadBufferPerConnection appropriately
	if s.HTTP2MaxStreamsPerConnection > 0 {
		http2Options.MaxConcurrentStreams = uint32(s.HTTP2MaxStreamsPerConnection)
	} else {
		// match http2.initialMaxConcurrentStreams used by clients

const commonSize = 32

const keySizeCounterNonceGCM = commonSize

// NewGCMTransformerWithUniqueKeyUnsafe is the same as NewGCMTransformer but is unsafe for general
// use because it makes assumptions about the key underlying the block cipher.  Specifically,
// it uses a 96-bit nonce where the first 32 bits are random data and the remaining 64 bits are

}

// end writes the buffer back into the m.
func (w traceWriter) end() {
	if w.mp == nil {
		// Tolerate a nil mp. It makes code that creates traceWriters directly
		// less error-prone.
		return
	}
	w.mp.trace.buf[w.gen%2] = w.traceBuf
}

// ensure makes sure that at least maxSize bytes are available to write.
//
// Returns whether the buffer was flushed.

        } 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 =