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, 6 insertions, 6 deletions

diff --git a/src/builder/get_messages.rs b/src/builder/get_messages.rs
index 71af9e5..e59584f 100644
--- a/src/builder/get_messages.rs
+++ b/src/builder/get_messages.rs
@@ -1,5 +1,5 @@
-use std::collections::BTreeMap;
 use model::MessageId;
+use std::collections::HashMap;
 
 /// Builds a request for a request to the API to retrieve messages.
 ///
@@ -50,13 +50,13 @@ use model::MessageId;
 ///
 /// [`GuildChannel::messages`]: ../model/struct.GuildChannel.html#method.messages
 #[derive(Clone, Debug, Default)]
-pub struct GetMessages(pub BTreeMap<String, u64>);
+pub struct GetMessages(pub HashMap<&'static str, u64>);
 
 impl GetMessages {
     /// Indicates to retrieve the messages after a specific message, given by
     /// its Id.
     pub fn after<M: Into<MessageId>>(mut self, message_id: M) -> Self {
-        self.0.insert("after".to_string(), message_id.into().0);
+        self.0.insert("after", message_id.into().0);
 
         self
     }
@@ -64,7 +64,7 @@ impl GetMessages {
     /// Indicates to retrieve the messages _around_ a specific message in either
     /// direction (before+after) the given message.
     pub fn around<M: Into<MessageId>>(mut self, message_id: M) -> Self {
-        self.0.insert("around".to_string(), message_id.into().0);
+        self.0.insert("around", message_id.into().0);
 
         self
     }
@@ -72,7 +72,7 @@ impl GetMessages {
     /// Indicates to retrieve the messages before a specific message, given by
     /// its Id.
     pub fn before<M: Into<MessageId>>(mut self, message_id: M) -> Self {
-        self.0.insert("before".to_string(), message_id.into().0);
+        self.0.insert("before", message_id.into().0);
 
         self
     }
@@ -86,7 +86,7 @@ impl GetMessages {
     /// reduced.
     pub fn limit(mut self, limit: u64) -> Self {
         self.0
-            .insert("limit".to_string(), if limit > 100 { 100 } else { limit });
+            .insert("limit", if limit > 100 { 100 } else { limit });
 
         self
     }