Time lag between PreRenderComplete and SaveState

Question

We are tracing our ASP.NET application and find that for one of our pages we see that there is a time lag of around 2.5 secs from the time PreRenderComplete Ends to SaveState Begins. Below is a part of log

aspx.page End PreRender 9.123185387 0.184541

aspx.page Begin PreRenderComplete 9.123277718 0.000092

aspx.page End PreRenderComplete 9.123666575 0.000389

aspx.page Begin SaveState 11.77441916 2.650753

aspx.page End SaveState 11.77457158 0.000152

aspx.page Begin SaveStateComplete 11.77459695 0.000025

aspx.page End SaveStateComplete 11.77461284 0.000016

aspx.page Begin Render 11.77462541 0.000013

aspx.page End Render 15.10157813 3.326953

we are trying to understand if there is any rationale behind this. Pls help me understand this.

Thanks in Advance