argumentMapping[valueArgument] = parameterSymbol
        }
    }

    private fun FirExpression.findSourceKtExpressionForCallArgument(): KtExpression? {
        // For smart-casted expression, refer to the source of the original expression
        // For spread, named, and lambda arguments, the source is the KtValueArgument.
        // For other arguments (including array indices), the source is the KtExpression.

 *  Fix: The previous release introduced a performance regression on Android,
    caused by looking up CA certificates. This is now fixed.


## Version 3.1.0

_2016-02-06_

 *  New: WebSockets now defer some writes. This should improve performance for
    some applications.
 *  New: Override `equals()` and `hashCode()` in our new cookie class. This
    class now defines equality by value rather than by reference.

  @get:JvmName("dns")
  val dns: Dns = builder.dns

  @get:JvmName("proxy")
  val proxy: Proxy? = builder.proxy

  @get:JvmName("proxySelector")
  val proxySelector: ProxySelector =
    when {
      // Defer calls to ProxySelector.getDefault() because it can throw a SecurityException.
      builder.proxy != null -> NullProxySelector
      else -> builder.proxySelector ?: ProxySelector.getDefault() ?: NullProxySelector
    }