  The efficiency of energy conversion during magnetic reconnection is related
to the reconnection rate. While the stable reconnection rate has been studied
extensively, its growth between the time of reconnection onset and the peak
reconnection rate has not been thoroughly discussed. We use a 2D
particle-in-cell (PIC) simulation to examine how the non-ideal reconnection
electric field evolves during the growth process and how it relates to changes
near the x-line. We identify three phases of growth: 1) slow quasi-linear
growth, 2) rapid exponential growth, and 3) tapered growth followed by negative
growth after the reconnection rate peaks. Through analysis of the structural
changes of the EDR, we associate the early phases with the breaking of x-line
symmetry through the erosion of the pre-onset bipolar Ez and the emergence of a
diverging Ex pattern at the neutral line in phase 1 followed by the expansion
of the inflow region and the enhancement of inflow Poynting flux Sz associated
with the out-of-plane electric field Ey in phase 2. We show how the Hall fields
facilitate rapid growth in phase 2 by opening up the exhaust, relieving the
electron-scale bottleneck and allowing large Poynting flux across the
separatrices. We find that the rapid inflow of electromagnetic energy
accumulates until the downstream electromagnetic energy density in phase 3
approaches the initial upstream asymptotic value. Finally, we examine how the
electron outflow and the downstream ion populations interact in phase 3 and how
each species exchanges energy with the local field structures in the exhaust.
