Implement Deref<Target=UrlClient> for EsploraBlockchain

There is currently no way to access the client
from the EsploraBlockchain. This makes it difficult
for users to extend it's functionality. This PR exposes
both the reqwest and ureq clients. This PR is related to
PR bitcoindevkit#705.

src/blockchain/esplora/reqwest.rs

@@ -31,8 +31,9 @@ use crate::database::BatchDatabase;
 use crate::error::Error;
 use crate::FeeRate;
 
+/// Structure that encapsulates Esplora client
 #[derive(Debug)]
-struct UrlClient {
+pub struct UrlClient {
     url: String,
     // We use the async client instead of the blocking one because it automatically uses `fetch`
     // when the target platform is wasm32.
@@ -101,6 +102,14 @@ impl Blockchain for EsploraBlockchain {
     }
 }
 
+impl Deref for EsploraBlockchain {
+    type Target = UrlClient;
+
+    fn deref(&self) -> &Self::Target {
+        &self.url_client
+    }
+}
+
 impl StatelessBlockchain for EsploraBlockchain {}
 
 #[maybe_async]

src/blockchain/esplora/ureq.rs

@@ -33,8 +33,9 @@ use crate::database::BatchDatabase;
 use crate::error::Error;
 use crate::FeeRate;
 
+/// Structure that encapsulates Esplora client
 #[derive(Debug, Clone)]
-struct UrlClient {
+pub struct UrlClient {
     url: String,
     agent: Agent,
 }
@@ -98,6 +99,14 @@ impl Blockchain for EsploraBlockchain {
     }
 }
 
+impl Deref for EsploraBlockchain {
+    type Target = UrlClient;
+
+    fn deref(&self) -> &Self::Target {
+        &self.url_client
+    }
+}
+
 impl StatelessBlockchain for EsploraBlockchain {}
 
 impl GetHeight for EsploraBlockchain {