Because the reactors' graphics are determined by metadata, assembling/breaking the reactor sends a giant wad of updates to the client whenever the reactor is assembled or broken.

With very large reactors (11x11 or bigger), this results in a noticeable hiccup/lag while the client processes all the updates.

To fix this, migrate the Reactor Part block and class to not use metadata to communicate state; instead, send a "reactor assembled" and "reactor disassembled" packet which triggers client-only visual updates based on the block's connection state.

This is a relatively large change and will require some significant rework, but should result in a faster, cleaner system.

This is fixed for 0.3.0 by the abandonment of metadata-based texturing.