Introduce TransmitBuilder::has_datagram_capacity

Replaces manually checking for number of allowed datagrams.

Author: flub

quinn-proto/src/connection/mod.rs

@@ -565,7 +565,7 @@ impl Connection {
                 // We need to send 1 more datagram and extend the buffer for that.
 
                 // Is 1 more datagram allowed?
-                if transmit.num_datagrams() >= transmit.max_datagrams() {
+                if transmit.has_datagram_capacity() {
                     // No more datagrams allowed
                     break;
                 }

quinn-proto/src/connection/transmit_builder.rs

@@ -160,6 +160,11 @@ impl<'a> TransmitBuilder<'a> {
         &self.buf[self.datagram_start..]
     }
 
+    /// Whether there is space for another datagram in this transmit
+    pub(super) fn has_datagram_capacity(&self) -> bool {
+        self.num_datagrams >= self.max_datagrams
+    }
+
     /// Returns the GSO segment size
     ///
     /// This is also the maximum size datagrams are allowed to be. The first and last
@@ -176,11 +181,6 @@ impl<'a> TransmitBuilder<'a> {
         self.num_datagrams
     }
 
-    /// Returns the maximum number of datagrams allowed to be written into the buffer
-    pub(super) fn max_datagrams(&self) -> usize {
-        self.max_datagrams
-    }
-
     /// Returns `true` if there are no datagrams in this transmit
     pub(super) fn is_empty(&self) -> bool {
         self.len() == 0