Add http proxy config

src/http_pool.nim

@@ -6,10 +6,17 @@ type
     conns*: seq[AsyncHttpClient]
 
 var maxConns {.threadvar.}: int
+var proxy {.threadvar.}: Proxy
 
 proc setMaxHttpConns*(n: int) =
   maxConns = n
 
+proc setHttpProxy*(url: string; auth: string) =
+  if url.len > 0:
+    proxy = newProxy(url, auth)
+  else:
+    proxy = nil
+
 proc release*(pool: HttpPool; client: AsyncHttpClient) =
   if pool.conns.len >= maxConns:
     client.close()
@@ -20,7 +27,7 @@ template use*(pool: HttpPool; heads: HttpHeaders; body: untyped): untyped =
   var c {.inject.}: AsyncHttpClient
 
   if pool.conns.len == 0:
-    c = newAsyncHttpClient(headers=heads)
+    c = newAsyncHttpClient(headers=heads, proxy=proxy)
   else:
     c = pool.conns.pop()
     c.headers = heads