$ mcs client.asmx -r:System.Net.Http -sdk:4.5
client.asmx(28,60): error CS0120: An object reference is required to access non-static member `ConsoleProgram.Class1.urlParameters'
client.asmx(32,52): error CS1061: Type `System.Net.Http.HttpContent' does not contain a definition for `ReadAsAsync' and no extension method `ReadAsAsync' of type `System.Net.Http.HttpContent' could be found. Are you missing an assembly reference?
/usr/lib/mono/4.5-api/System.Net.Http.dll (Location of the symbol related to previous error)
Compilation failed: 2 error(s), 0 warnings