adjust readme

README.md

@@ -21,7 +21,7 @@ Generic value log implementation for key-value separated storage, inspired by Ro
 - 100% safe & stable Rust
 - Supports generic KV-index structures (LSM-tree, ...)
 - Built-in per-blob compression (LZ4)
-- In-memory blob cache for hot data, that can be shared between multiple value logs
+- In-memory blob cache for hot data - can be shared between multiple value logs to cap memory usage
 
 Keys are limited to 65536 bytes, values are limited to 2^32 bytes.
 
@@ -33,6 +33,12 @@ Allows using `LZ4` compression, powered by [`lz4_flex`](https://github.com/PSeit
 
 *Enabled by default.*
 
+### serde
+
+Enables `serde` derives.
+
+*Disabled by default.*
+
 ## Stable disk format
 
 The disk format is stable as of 1.0.0. Future breaking changes will result in a major version bump and a migration path.