gRPC performance and related documentation.

[MakMukhi]

• Possible optimizations:
  • BDP estimation and dynamic flow control. This is especially important for high-latency networks(cross-continental communication).
  • Further optimize Unary RPCs to expect a large response from the server.
  • Batching writes.
• Our efforts should prioritize optimizations that alleviate performance problems in high-latency networks since that closely aligns with user needs.
• Documentation.
• More benchmarks. (Create comprehensive benchmarks #1285 covers this now)