Simplify tcp::Socket::can_recv

This function does not actually care about the socket state, so there
is no need to check it. The ability to immediately receive data only
depends on there being something in the receive buffer.

Author: smaeul

src/socket/tcp.rs

@@ -1185,7 +1185,7 @@ impl<'a> Socket<'a> {
             // we still can receive indefinitely.
             State::FinWait1 | State::FinWait2 => true,
             // If we have something in the receive buffer, we can receive that.
-            _ if !self.rx_buffer.is_empty() => true,
+            _ if self.can_recv() => true,
             _ => false,
         }
     }
@@ -1213,14 +1213,9 @@ impl<'a> Socket<'a> {
         self.tx_buffer.capacity()
     }
 
-    /// Check whether the receive half of the full-duplex connection buffer is open
-    /// (see [may_recv](#method.may_recv)), and the receive buffer is not empty.
+    /// Check whether the receive buffer is not empty.
     #[inline]
     pub fn can_recv(&self) -> bool {
-        if !self.may_recv() {
-            return false;
-        }
-
         !self.rx_buffer.is_empty()
     }