ESI module flow

gistfile1.txt

      .------------------------.
      |       Page Call        |
      '------------------------'
                   |
                   v               ____________________________
              .---------.          \                           \
             / Call to   \          \  ESI module ask plugin to \
            (  ESI PATH?  )--------->) build content             )
             \           /          /                           /
              '---------'          /___________________________/
.------------------|------------------------------|-----------------.
|                  |     ESI plugin Modules       |                 |
|------------------|------------------------------|-----------------|
|                  v                              v                 |
|    _________________________      _________________________       |
|    \                        \     \                        \      |
|     \  Various plugins alter \     \  plugin build content  \     |
|      ) render arrays to be    )     ) for esi request        )    |
|     /  ESI ones              /     /                        /     |
|    /________________________/     /________________________/      |
|                  |                              |                 |
'------------------|------------------------------|-----------------'
                   v                              |
     __________________________                   |
     \                         \                  |
      \                         \                 |
       ) Drupal Renders ESI tags )                |
      /                         /                 |
     /_________________________/                  |
                   |                              |
                   |                              |
                   v                              |
      .------------------------.                  |
      |      Page Return       |<-----------------'
      '------------------------'