General performance issue

While looking into some performance challenges I noticed some slow operations or at least operations that can cause peak load.

• JSON-LD processing is really slow. The json-gold library creates the context and validates VCs every time. The validating step does a lot of regexes.
• we do a lot of json (un)marshalling. For VC/JSON-LD processing, DID resolving and internals where we marshal/unmarshal to/from interface{}
• the memory allocations for json processing also causes GC cycles.

There are some quick fixes:

• cache DID resolve after unmarshal
• fork json-gold and disable some validation checks
• check functions/methods on interface{} arguments and remove some of the marshal/unmarshal operations where possible.

Start by profiling JSON-LD processing, DID resolving, and the VC/JSON-LD paths that marshal or unmarshal through interface{}. Compare the cost of json-gold validation, repeated DID resolution, and JSON allocations before choosing a focused change; done should be demonstrated by lower measured latency, peak load, or allocation and GC costs.