code: @DoesServiceRequest
      public final CloudFileShare createSnapshot(final HashMap<String, String> metadata,
              final AccessCondition accessCondition, FileRequestOptions options, OperationContext opContext)
              throws StorageException {
          assertNoSnapshot();
  
          if (opContext == null) {
              opContext = new OperationContext();
          }
  
          opContext.initialize();
          options = FileRequestOptions.populateAndApplyDefaults(options, this.fileServiceClient);
  
          return ExecutionEngine
                  .executeWithRetry(this.fileServiceClient, this,
                          this.createSnapshotImpl(metadata, accessCondition, options), options.getRetryPolicyFactory(),
                          opContext);
      }
docs: Creates a snapshot of the file share using the specified request options and operation context.
  
  @param metadata
  A collection of name-value pairs defining the metadata of the snapshot, or null.
  @param accessCondition
  An {@link AccessCondition} object that represents the access conditions for the file share.
  @param options
  A {@link FileRequestOptions} object that specifies any additional options for the request. Specifying
  <code>null</code> will use the default request options from the associated service client (
  {@link CloudFileClient}).
  @param opContext
  An {@link OperationContext} object that represents the context for the current operation. This object
  is used to track requests to the storage service, and to provide additional runtime information about
  the operation.
  
  @return A <code>CloudFileShare</code> object that represents the snapshot of the file share.
  
  @throws StorageException
  If a storage service error occurred.