title: Thrift go support of map with struct value as key
body: <p>I experimented golang generation with Thrift 0.9.1, for example,</p>
  
  <p>thrift definition,</p>
  
  <pre><code>struct AppIdLeveledHashKeyTimeKeyHour {
      1: required i32 appId
      2: required LeveledHashKey leveledHashKey
      3: required TimeKeyHour timeKeyHour
  }
  typedef map&lt;AppIdLeveledHashKeyTimeKeyHour, ...sth else...&gt; EventSliceShardIdValue
  </code></pre>
  
  <p>in the generated code, EventSliceShardIdValue would be,</p>
  
  <pre><code>type EventSliceShardIdValue map[*AppIdLeveledHashKeyTimeKeyHour]EventSliceAppIdLeveledHashKeyTimeKeyHourValue
  </code></pre>
  
  <p>you can find the key part is a pointer which represents memory address. In golang a pointer as map key (instead of a value, or hash of the obj) is useless in most cases. To use a combination of some fields as map key, the definition should use a value type like</p>
  
  <pre><code>map[AppIdLeveledHashKeyTimeKeyHour]EventSliceAppIdLeveledHashKeyTimeKeyHourValue
  </code></pre>
  
  <p>Is it a problem of Thrift's go support (or I misused sth)? Any workaround to solve this problem in thrift? </p>