Implement BlockSource for REST and RPC clients

Interprets HTTP responses as either binary or JSON format, which are
then converted to the appropriate data types.

Author: jkczyz

lightning-block-sync/Cargo.toml

@@ -9,13 +9,14 @@ Utilities to fetch the chain data from a block source and feed them into Rust Li
 """
 
 [features]
-rest-client = [ "serde_json", "chunked_transfer" ]
-rpc-client = [ "serde_json", "chunked_transfer" ]
+rest-client = [ "serde", "serde_json", "chunked_transfer" ]
+rpc-client = [ "serde", "serde_json", "chunked_transfer" ]
 
 [dependencies]
 bitcoin = "0.24"
 lightning = { version = "0.0.12", path = "../lightning" }
 tokio = { version = "1.0", features = [ "io-util", "net" ], optional = true }
+serde = { version = "1.0", features = ["derive"], optional = true }
 serde_json = { version = "1.0", optional = true }
 chunked_transfer = { version = "1.4", optional = true }
 futures = { version = "0.3" }