Slightly improve performance of builders

Builders would keep a `serde_json::Map<String, Value>`, which would
require re-creating owned strings for the same parameter multiple times
in some cases, depending on builder defaults and keying strategies.

This commit uses a `std::collections::HashMap<&'static str, Value>`
internally, and moves over values to a `serde_json::Map<String, Value>`
when it comes time to sending them to the appropriate `http` module
function.

This saves the number of heap-allocated string creations on most
builders, with specific performance increase on `builder::CreateMessage`
and `builder::CreateEmbed` & co.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/model/channel/message.rs b/src/model/channel/message.rs
index 0e939b2..b5864fc 100644
--- a/src/model/channel/message.rs
+++ b/src/model/channel/message.rs
@@ -14,6 +14,8 @@ use constants;
 use CACHE;
 #[cfg(feature = "model")]
 use http;
+#[cfg(feature = "model")]
+use utils as serenity_utils;
 
 /// A representation of a message over a guild's text channel, a group, or a
 /// private channel.
@@ -230,7 +232,7 @@ impl Message {
             builder = builder.tts(true);
         }
 
-        let map = f(builder).0;
+        let map = serenity_utils::hashmap_to_json_map(f(builder).0);
 
         match http::edit_message(self.channel_id.0, self.id.0, &Value::Object(map)) {
             Ok(edited) => {