*
   * <pre>
   * com....PotentialDeadlockException: Potential Deadlock from LockC -&gt; ReadWriteA
   *   at ...
   *   at ...
   * Caused by: com...ExampleStackTrace: LockB -&gt; LockC
   *   at ...
   *   at ...
   * Caused by: com...ExampleStackTrace: ReadWriteA -&gt; LockB
   *   at ...
   *   at ...
   * </pre>
   *

Interceptors
============

Interceptors are a powerful mechanism that can monitor, rewrite, and retry calls. Here's a simple interceptor that logs the outgoing request and the incoming response.

```java
class LoggingInterceptor implements Interceptor {
  @Override public Response intercept(Interceptor.Chain chain) throws IOException {
    Request request = chain.request();

    long t1 = System.nanoTime();

pkg bufio, method (*Writer) AvailableBuffer() []uint8
pkg bufio, method (ReadWriter) AvailableBuffer() []uint8
pkg bytes, func Cut([]uint8, []uint8) ([]uint8, []uint8, bool)
pkg bytes, func Title //deprecated
pkg crypto/tls, method (*Conn) NetConn() net.Conn
pkg crypto/tls, type Config struct, PreferServerCipherSuites //deprecated
pkg crypto/x509, method (*CertPool) Subjects //deprecated
pkg debug/buildinfo, func Read(io.ReaderAt) (*debug.BuildInfo, error)

For example, a compiler must not invert the conditional in this program:
</p>

<pre>
*p = 1
if cond {
	*p = 2
}
</pre>

<p>
That is, the compiler must not rewrite the program into this one:
</p>

<pre>
*p = 2
if !cond {
	*p = 1
}
</pre>

<p>
If <code>cond</code> is false and another goroutine is reading <code>*p</code>,

introduce a Go variable that points at the C variable (the linker can
be told to initialize this pointer).  For example, if the gmp library
provided

	mpz_t zero;

then cgo would rewrite a reference to C.zero by introducing

	var _C_zero *C.mpz_t

and then replacing all instances of C.zero with (*_C_zero).

Cgo's most interesting translation is for functions.  If xxx is a C

}

// RenameDataResp - RenameData()'s response.
// Provides information about the final state of Rename()
//   - on xl.meta (array of versions) on disk to check for version disparity
//   - on rewrite dataDir on disk that must be additionally purged
//     only after as a 2-phase call, allowing the older dataDir to
//     hang-around in-case we need some form of recovery.
type RenameDataResp struct {

    `requestBodyEnd()`, both on the same call. Such events may be triggered by different threads
    even for a single call.

    Interceptors that rewrite or replace the request body may now inadvertently interfere with
    duplex request bodies. Such interceptors should check `RequestBody.isDuplex()` and avoid
    accessing the request body when it is.

	// TODO BML I don't think we need UDP? TCP healthcheck redir should catch everything.

	// This is effectively an analog for Istio's old-style podSpec-based health check rewrites.
	// Before Istio would update the pod manifest to rewrite healthchecks to go to sidecar Envoy port 15021,
	// so that it could distinguish things that can be unauthenticated (healthchecks) from other kinds of node traffic

	for i, param := range params {
		if p.needsPointerCheck(f, param.Go, args[i]) {
			any = true
			break
		}
	}
	if !any {
		return "", false
	}

	// We need to rewrite this call.
	//
	// Rewrite C.f(p) to
	//    func() {
	//            _cgo0 := p
	//            _cgoCheckPointer(_cgo0, nil)
	//            C.f(_cgo0)
	//    }()
	// Using a function literal like this lets us evaluate the

   * long, long)} using the requested {@link MapMode}.
   *
   * <p>Files are mapped from offset 0 to {@code size}.
   *
   * <p>If the mode is {@link MapMode#READ_WRITE} and the file does not exist, it will be created
   * with the requested {@code size}. Thus this method is useful for creating memory mapped files
   * which do not yet exist.
   *