* installation
* activation
* update
* deactivation
* un-installation

When a plugin is installed we may want to check the license and make users agree. We may also want to unpack the given plugin in a particular location.

  Operating System:
    Windows:
      Windows 2000 or above.
    Unix based systems (Linux, Solaris and Mac OS X) and others:
      No minimum requirement.

  Installing Maven
  ----------------

  1) Unpack the archive where you would like to store the binaries, e.g.:

    Unix-based operating systems (Linux, Solaris and Mac OS X)
      tar zxvf apache-maven-4.x.y.tar.gz
    Windows
      unzip apache-maven-4.x.y.zip

     * from the information that is available at the point the problem occurs and as such merely serves as a best effort
     * to provide information to the user to track the problem back to its origin.
     *
     * @return The identifier of the model from which the problem originated or an empty string if unknown, never
     *         {@code null}.
     */
    String getModelId();

      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-dependency-plugin</artifactId>
        <executions>
          <execution>
            <id>unpack-jansi-native</id>
            <goals>
              <goal>unpack-dependencies</goal>
            </goals>
            <configuration>
              <includeArtifactIds>jansi</includeArtifactIds>

                // ignore
            }
        }
        cache.clear();
    }

    public void register(MavenProject project, Key key, CacheRecord record) {
        // default cache does not track extension usage
    }

    public void dispose() {
        flush();
    }

    </default>
  </defaults>
  <classes>
    <class java.clone="deep">
      <name>TrackableBase</name>
      <version>1.0.0+</version>
      <description>
        common base class that contains code to track the source for
        this instance (USER|GLOBAL)
      </description>
      <codeSegments>
        <codeSegment>
          <version>1.0.0/1.3.0</version>
          <code>

     * creator of the problem, the general expectation is that the hint provides sufficient information to the user to
     * track the problem back to its origin. A concrete example for such a source hint can be the file path or URL from
     * which the settings were read.
     *

            }
            trace = trace.getParent();
        }

        Path trackingDir;
        boolean missing = event.getFile() == null;
        if (missing) {
            // missing artifact - let's track the path anyway
            File dir = event.getSession().getLocalRepository().getBasedir();
            dir = new File(

                // ignore
            }
        }
        cache.clear();
    }

    public void register(MavenProject project, Key key, CacheRecord record) {
        // default cache does not track record usage
    }

    @Override
    public void dispose() {
        flush();
    }

        return CacheUtils.pluginEquals(a, b);
    }

    public void register(MavenProject project, Key key, CacheRecord record) {
        // default cache does not track plugin usage
    }

    public void dispose() {
        flush();
    }