Naming a field "from" renders .proto uncompilable

[Redoubts]

The following proto file won't compile with pyrobuf:

syntax = "proto2";

package test;

message Item {
    optional double from = 1;
}

due to this error:

Error compiling Cython file:
------------------------------------------------------------
...
        self._from = 0
        return

    @property
    def from(self):
       ^
------------------------------------------------------------

out/test_proto.pyx:54:8: Expected an identifier